docs/backbone.html
Backbone.js 1.6.1
(c) 2010-2024 Jeremy Ashkenas and DocumentCloud
Backbone may be freely distributed under the MIT license.
For all details and documentation:
http://backbonejs.org
(function(factory) {
Establish the root object, window (self) in the browser, or global on the server. We use self instead of window for WebWorker support.
varroot =typeofself =='object'&& self.self=== self && self ||typeofglobal=='object'&&global.global===global&&global;
Set up Backbone appropriately for the environment. Start with AMD.
if(typeofdefine ==='function'&& define.amd) {define(['underscore','jquery','exports'],function(\_, $, exports) {
Export global even in AMD case in case this script is loaded with others that may still expect a global Backbone.
root.Backbone=factory(root,exports, _, $);
});
Next for Node.js or CommonJS. jQuery may not be needed as a module.
}elseif(typeofexports!=='undefined') {var_ =require('underscore'), $;try{ $ =require('jquery'); }catch(e) {}factory(root,exports, _, $);
Finally, as a browser global.
}else{
root.Backbone=factory(root, {}, root.\_, root.jQuery|| root.Zepto|| root.ender|| root.$);
}
})(function(root, Backbone, \_, $) {
Save the previous value of the Backbone variable, so that it can be restored later on, if noConflict is used.
varpreviousBackbone = root.Backbone;
Create a local reference to a common array method we’ll want to use later.
varslice =Array.prototype.slice;
Current version of the library. Keep in sync with package.json.
Backbone.VERSION='1.6.1';
For Backbone’s purposes, jQuery, Zepto, Ender, or My Library (kidding) owns the $ variable.
Backbone.$= $;
Runs Backbone.js in noConflict mode, returning the Backbone variable to its previous owner. Returns a reference to this Backbone object.
Backbone.noConflict=function() {
root.Backbone= previousBackbone;returnthis;
};
Turn on emulateHTTP to support legacy HTTP servers. Setting this option will fake "PATCH", "PUT" and "DELETE" requests via the _method parameter and set a X-Http-Method-Override header.
Backbone.emulateHTTP=false;
Turn on emulateJSON to support legacy servers that can’t deal with direct application/json requests … this will encode the body as application/x-www-form-urlencoded instead and will send the model in a form param named model.
Backbone.emulateJSON=false;
A module that can be mixed in to any object in order to provide it with a custom event channel. You may bind a callback to an event with on or remove with off; trigger-ing an event fires all callbacks in succession.
var object = {};
_.extend(object, Backbone.Events);
object.on('expand', function(){ alert('expanded'); });
object.trigger('expand');
varEvents=Backbone.Events= {};
Regular expression used to split event strings.
vareventSplitter =/\s+/;
A private global variable to share between listeners and listenees.
var_listening;
Iterates over the standard event, callback (as well as the fancy multiple space-separated events "change blur", callback and jQuery-style event maps {event: callback}).
vareventsApi =function(iteratee, events, name, callback, opts) {vari =0, names;if(name &&typeofname ==='object') {
Handle event maps.
if(callback !==void0&&'context'inopts && opts.context===void0) opts.context= callback;for(names = _.keys(name); i < names.length; i++) {
events =eventsApi(iteratee, events, names[i], name[names[i]], opts);
}
}elseif(name && eventSplitter.test(name)) {
Handle space-separated event names by delegating them individually.
for(names = name.split(eventSplitter); i < names.length; i++) {
events =iteratee(events, names[i], callback, opts);
}
}else{
Finally, standard events.
events =iteratee(events, name, callback, opts);
}returnevents;
};
Bind an event to a callback function. Passing "all" will bind the callback to all events fired.
Events.on=function(name, callback, context) {this.\_events=eventsApi(onApi,this.\_events|| {}, name, callback, {context: context,ctx:this,listening: _listening
});if(_listening) {varlisteners =this.\_listeners|| (this.\_listeners= {});
listeners[_listening.id] = _listening;
Allow the listening to use a counter, instead of tracking callbacks for library interop
_listening.interop=false;
}returnthis;
};
Inversion-of-control versions of on. Tell this object to listen to an event in another object… keeping track of what it’s listening to for easier unbinding later.
Events.listenTo=function(obj, name, callback) {if(!obj)returnthis;varid = obj.\_listenId|| (obj.\_listenId= _.uniqueId('l'));varlisteningTo =this.\_listeningTo|| (this.\_listeningTo= {});varlistening = _listening = listeningTo[id];
This object is not listening to any other events on obj yet. Setup the necessary references to track the listening callbacks.
if(!listening) {this.\_listenId|| (this.\_listenId= _.uniqueId('l'));
listening = _listening = listeningTo[id] =newListening(this, obj);
}
Bind callbacks on obj.
varerror =tryCatchOn(obj, name, callback,this);
_listening =void0;if(error)throwerror;
If the target obj is not Backbone.Events, track events manually.
if(listening.interop) listening.on(name, callback);returnthis;
};
The reducing API that adds a callback to the events object.
varonApi =function(events, name, callback, options) {if(callback) {varhandlers = events[name] || (events[name] = []);varcontext = options.context, ctx = options.ctx, listening = options.listening;if(listening) listening.count++;
handlers.push({callback: callback,context: context,ctx: context || ctx,listening: listening});
}returnevents;
};
An try-catch guarded #on function, to prevent poisoning the global _listening variable.
vartryCatchOn =function(obj, name, callback, context) {try{
obj.on(name, callback, context);
}catch(e) {returne;
}
};
Remove one or many callbacks. If context is null, removes all callbacks with that function. If callback is null, removes all callbacks for the event. If name is null, removes all bound callbacks for all events.
Events.off=function(name, callback, context) {if(!this.\_events)returnthis;this.\_events=eventsApi(offApi,this.\_events, name, callback, {context: context,listeners:this.\_listeners});returnthis;
};
Tell this object to stop listening to either specific events … or to every object it’s currently listening to.
Events.stopListening=function(obj, name, callback) {varlisteningTo =this.\_listeningTo;if(!listeningTo)returnthis;varids = obj ? [obj.\_listenId] : _.keys(listeningTo);for(vari =0; i < ids.length; i++) {varlistening = listeningTo[ids[i]];
If listening doesn’t exist, this object is not currently listening to obj. Break out early.
if(!listening)break;
listening.obj.off(name, callback,this);if(listening.interop) listening.off(name, callback);
}if(_.isEmpty(listeningTo))this.\_listeningTo=void0;returnthis;
};
The reducing API that removes a callback from the events object.
varoffApi =function(events, name, callback, options) {if(!events)return;varcontext = options.context, listeners = options.listeners;vari =0, names;
Delete all event listeners and “drop” events.
if(!name && !context && !callback) {for(names = _.keys(listeners); i < names.length; i++) {
listeners[names[i]].cleanup();
}return;
}
names = name ? [name] : _.keys(events);for(; i < names.length; i++) {
name = names[i];varhandlers = events[name];
Bail out if there are no events stored.
if(!handlers)break;
Find any remaining events.
varremaining = [];for(varj =0; j < handlers.length; j++) {varhandler = handlers[j];if(
callback && callback !== handler.callback&&
callback !== handler.callback.\_callback||
context && context !== handler.context) {
remaining.push(handler);
}else{varlistening = handler.listening;if(listening) listening.off(name, callback);
}
}
Replace events if there are any remaining. Otherwise, clean up.
if(remaining.length) {
events[name] = remaining;
}else{deleteevents[name];
}
}returnevents;
};
Bind an event to only be triggered a single time. After the first time the callback is invoked, its listener will be removed. If multiple events are passed in using the space-separated syntax, the handler will fire once for each event, not once for a combination of all events.
Events.once=function(name, callback, context) {
Map the event into a {event: once} object.
varevents =eventsApi(onceMap, {}, name, callback,this.off.bind(this));if(typeofname ==='string'&& context ==null) callback =void0;returnthis.on(events, callback, context);
};
Inversion-of-control versions of once.
Events.listenToOnce=function(obj, name, callback) {
Map the event into a {event: once} object.
varevents =eventsApi(onceMap, {}, name, callback,this.stopListening.bind(this, obj));returnthis.listenTo(obj, events);
};
Reduces the event callbacks into a map of {event: onceWrapper}. offer unbinds the onceWrapper after it has been called.
varonceMap =function(map, name, callback, offer) {if(callback) {varonce = map[name] = _.once(function() {offer(name, once);
callback.apply(this,arguments);
});
once.\_callback= callback;
}returnmap;
};
Trigger one or many events, firing all bound callbacks. Callbacks are passed the same arguments as trigger is, apart from the event name (unless you’re listening on "all", which will cause your callback to receive the true name of the event as the first argument).
Events.trigger=function(name) {if(!this.\_events)returnthis;varlength =Math.max(0,arguments.length-1);varargs =Array(length);for(vari =0; i < length; i++) args[i] =arguments[i +1];eventsApi(triggerApi,this.\_events, name,void0, args);returnthis;
};
Handles triggering the appropriate event callbacks.
vartriggerApi =function(objEvents, name, callback, args) {if(objEvents) {varevents = objEvents[name];varallEvents = objEvents.all;if(events && allEvents) allEvents = allEvents.slice();if(events)triggerEvents(events, args);if(allEvents)triggerEvents(allEvents, [name].concat(args));
}returnobjEvents;
};
A difficult-to-believe, but optimized internal dispatch function for triggering events. Tries to keep the usual cases speedy (most internal Backbone events have 3 arguments).
vartriggerEvents =function(events, args) {varev, i = -1, l = events.length, a1 = args[0], a2 = args[1], a3 = args[2];switch(args.length) {case0:while(++i < l) (ev = events[i]).callback.call(ev.ctx);return;case1:while(++i < l) (ev = events[i]).callback.call(ev.ctx, a1);return;case2:while(++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2);return;case3:while(++i < l) (ev = events[i]).callback.call(ev.ctx, a1, a2, a3);return;default:while(++i < l) (ev = events[i]).callback.apply(ev.ctx, args);return;
}
};
A listening class that tracks and cleans up memory bindings when all callbacks have been offed.
varListening=function(listener, obj) {this.id= listener.\_listenId;this.listener= listener;this.obj= obj;this.interop=true;this.count=0;this.\_events=void0;
};Listening.prototype.on=Events.on;
Offs a callback (or several). Uses an optimized counter if the listenee uses Backbone.Events. Otherwise, falls back to manual tracking to support events library interop.
Listening.prototype.off=function(name, callback) {varcleanup;if(this.interop) {this.\_events=eventsApi(offApi,this.\_events, name, callback, {context:void0,listeners:void0});
cleanup = !this.\_events;
}else{this.count--;
cleanup =this.count===0;
}if(cleanup)this.cleanup();
};
Cleans up memory bindings between the listener and the listenee.
Listening.prototype.cleanup=function() {deletethis.listener.\_listeningTo[this.obj.\_listenId];if(!this.interop)deletethis.obj.\_listeners[this.id];
};
Aliases for backwards compatibility.
Events.bind=Events.on;Events.unbind=Events.off;
Allow the Backbone object to serve as a global event bus, for folks who want global “pubsub” in a convenient place.
_.extend(Backbone,Events);
Backbone Models are the basic data object in the framework – frequently representing a row in a table in a database on your server. A discrete chunk of data and a bunch of useful, related methods for performing computations and transformations on that data.
Create a new model with the specified attributes. A client id (cid) is automatically generated and assigned for you.
varModel=Backbone.Model=function(attributes, options) {varattrs = attributes || {};
options || (options = {});this.preinitialize.apply(this,arguments);this.cid= _.uniqueId(this.cidPrefix);this.attributes= {};if(options.collection)this.collection= options.collection;if(options.parse) attrs =this.parse(attrs, options) || {};vardefaults = _.result(this,'defaults');
Just _.defaults would work fine, but the additional _.extends is in there for historical reasons. See #3843.
attrs = _.defaults(_.extend({}, defaults, attrs), defaults);this.set(attrs, options);this.changed= {};this.initialize.apply(this,arguments);
};
Attach all inheritable methods to the Model prototype.
_.extend(Model.prototype,Events, {
A hash of attributes whose current and previous value differ.
changed:null,
The value returned during the last failed validation.
validationError:null,
The default name for the JSON id attribute is "id". MongoDB and CouchDB users may want to set this to "_id".
idAttribute:'id',
The prefix is used to create the client id which is used to identify models locally. You may want to override this if you’re experiencing name clashes with model ids.
cidPrefix:'c',
preinitialize is an empty function by default. You can override it with a function or object. preinitialize will run before any instantiation logic is run in the Model.
preinitialize:function(){},
Initialize is an empty function by default. Override it with your own initialization logic.
initialize:function(){},
Return a copy of the model’s attributes object.
toJSON:function(options) {return_.clone(this.attributes);
},
Proxy Backbone.sync by default – but override this if you need custom syncing semantics for this particular model.
sync:function() {returnBackbone.sync.apply(this,arguments);
},
Get the value of an attribute.
get:function(attr) {returnthis.attributes[attr];
},
Get the HTML-escaped value of an attribute.
escape:function(attr) {return_.escape(this.get(attr));
},
Returns true if the attribute contains a value that is not null or undefined.
has:function(attr) {returnthis.get(attr) !=null;
},
Special-cased proxy to underscore’s _.matches method.
matches:function(attrs) {return!!_.iteratee(attrs,this)(this.attributes);
},
Set a hash of model attributes on the object, firing "change". This is the core primitive operation of a model, updating the data and notifying anyone who needs to know about the change in state. The heart of the beast.
set:function(key, val, options) {if(key ==null)returnthis;
Handle both "key", value and {key: value} -style arguments.
varattrs;if(typeofkey ==='object') {
attrs = key;
options = val;
}else{
(attrs = {})[key] = val;
}
options || (options = {});
Run validation.
if(!this.\_validate(attrs, options))returnfalse;
Extract attributes and options.
varunset = options.unset;varsilent = options.silent;varchanges = [];varchanging =this.\_changing;this.\_changing=true;if(!changing) {this.\_previousAttributes= _.clone(this.attributes);this.changed= {};
}varcurrent =this.attributes;varchanged =this.changed;varprev =this.\_previousAttributes;
For each set attribute, update or delete the current value.
for(varattrinattrs) {
val = attrs[attr];if(!_.isEqual(current[attr], val)) changes.push(attr);if(!_.isEqual(prev[attr], val)) {
changed[attr] = val;
}else{deletechanged[attr];
}
unset ?deletecurrent[attr] : current[attr] = val;
}
Update the id.
if(this.idAttributeinattrs) {varprevId =this.id;this.id=this.get(this.idAttribute);if(this.id!== prevId) {this.trigger('changeId',this, prevId, options);
}
}
Trigger all relevant attribute changes.
if(!silent) {if(changes.length)this.\_pending= options;for(vari =0; i < changes.length; i++) {this.trigger('change:'+ changes[i],this, current[changes[i]], options);
}
}
You might be wondering why there’s a while loop here. Changes can be recursively nested within "change" events.
if(changing)returnthis;if(!silent) {while(this.\_pending) {
options =this.\_pending;this.\_pending=false;this.trigger('change',this, options);
}
}this.\_pending=false;this.\_changing=false;returnthis;
},
Remove an attribute from the model, firing "change". unset is a noop if the attribute doesn’t exist.
unset:function(attr, options) {returnthis.set(attr,void0, _.extend({}, options, {unset:true}));
},
Clear all attributes on the model, firing "change".
clear:function(options) {varattrs = {};for(varkeyinthis.attributes) attrs[key] =void0;returnthis.set(attrs, _.extend({}, options, {unset:true}));
},
Determine if the model has changed since the last "change" event. If you specify an attribute name, determine if that attribute has changed.
hasChanged:function(attr) {if(attr ==null)return!_.isEmpty(this.changed);return_.has(this.changed, attr);
},
Return an object containing all the attributes that have changed, or false if there are no changed attributes. Useful for determining what parts of a view need to be updated and/or what attributes need to be persisted to the server. Unset attributes will be set to undefined. You can also pass an attributes object to diff against the model, determining if there would be a change.
changedAttributes:function(diff) {if(!diff)returnthis.hasChanged() ? _.clone(this.changed) :false;varold =this.\_changing?this.\_previousAttributes:this.attributes;varchanged = {};varhasChanged;for(varattrindiff) {varval = diff[attr];if(_.isEqual(old[attr], val))continue;
changed[attr] = val;
hasChanged =true;
}returnhasChanged ? changed :false;
},
Get the previous value of an attribute, recorded at the time the last "change" event was fired.
previous:function(attr) {if(attr ==null|| !this.\_previousAttributes)returnnull;returnthis.\_previousAttributes[attr];
},
Get all of the attributes of the model at the time of the previous "change" event.
previousAttributes:function() {return_.clone(this.\_previousAttributes);
},
Fetch the model from the server, merging the response with the model’s local attributes. Any changed attributes will trigger a “change” event.
fetch:function(options) {
options = _.extend({parse:true}, options);varmodel =this;varsuccess = options.success;
options.success=function(resp) {varserverAttrs = options.parse? model.parse(resp, options) : resp;if(!model.set(serverAttrs, options))returnfalse;if(success) success.call(options.context, model, resp, options);
model.trigger('sync', model, resp, options);
};wrapError(this, options);returnthis.sync('read',this, options);
},
Set a hash of model attributes, and sync the model to the server. If the server returns an attributes hash that differs, the model’s state will be set again.
save:function(key, val, options) {
Handle both "key", value and {key: value} -style arguments.
varattrs;if(key ==null||typeofkey ==='object') {
attrs = key;
options = val;
}else{
(attrs = {})[key] = val;
}
options = _.extend({validate:true,parse:true}, options);varwait = options.wait;
If we’re not waiting and attributes exist, save acts as set(attr).save(null, opts) with validation. Otherwise, check if the model will be valid when the attributes, if any, are set.
if(attrs && !wait) {if(!this.set(attrs, options))returnfalse;
}elseif(!this.\_validate(attrs, options)) {returnfalse;
}
After a successful server-side save, the client is (optionally) updated with the server-side state.
varmodel =this;varsuccess = options.success;varattributes =this.attributes;
options.success=function(resp) {
Ensure attributes are restored during synchronous saves.
model.attributes= attributes;varserverAttrs = options.parse? model.parse(resp, options) : resp;if(wait) serverAttrs = _.extend({}, attrs, serverAttrs);if(serverAttrs && !model.set(serverAttrs, options))returnfalse;if(success) success.call(options.context, model, resp, options);
model.trigger('sync', model, resp, options);
};wrapError(this, options);
Set temporary attributes if {wait: true} to properly find new ids.
if(attrs && wait)this.attributes= _.extend({}, attributes, attrs);varmethod =this.isNew() ?'create': options.patch?'patch':'update';if(method ==='patch'&& !options.attrs) options.attrs= attrs;varxhr =this.sync(method,this, options);
Restore attributes.
this.attributes= attributes;returnxhr;
},
Destroy this model on the server if it was already persisted. Optimistically removes the model from its collection, if it has one. If wait: true is passed, waits for the server to respond before removal.
destroy:function(options) {
options = options ? _.clone(options) : {};varmodel =this;varsuccess = options.success;varwait = options.wait;vardestroy =function() {
model.stopListening();
model.trigger('destroy', model, model.collection, options);
};
options.success=function(resp) {if(wait)destroy();if(success) success.call(options.context, model, resp, options);if(!model.isNew()) model.trigger('sync', model, resp, options);
};varxhr =false;if(this.isNew()) {
_.defer(options.success);
}else{wrapError(this, options);
xhr =this.sync('delete',this, options);
}if(!wait)destroy();returnxhr;
},
Default URL for the model’s representation on the server – if you’re using Backbone’s restful methods, override this to change the endpoint that will be called.
url:function() {varbase =
_.result(this,'urlRoot') ||
_.result(this.collection,'url') ||urlError();if(this.isNew())returnbase;varid =this.get(this.idAttribute);returnbase.replace(/[^\/]$/,'$&/') +encodeURIComponent(id);
},
parse converts a response into the hash of attributes to be set on the model. The default implementation is just to pass the response along.
parse:function(resp, options) {returnresp;
},
Create a new model with identical attributes to this one.
clone:function() {returnnewthis.constructor(this.attributes);
},
A model is new if it has never been saved to the server, and lacks an id.
isNew:function() {return!this.has(this.idAttribute);
},
Check if the model is currently in a valid state.
isValid:function(options) {returnthis.\_validate({}, _.extend({}, options, {validate:true}));
},
Run validation against the next complete set of model attributes, returning true if all is well. Otherwise, fire an "invalid" event.
\_validate:function(attrs, options) {if(!options.validate|| !this.validate)returntrue;
attrs = _.extend({},this.attributes, attrs);varerror =this.validationError=this.validate(attrs, options) ||null;if(!error)returntrue;this.trigger('invalid',this, error, _.extend(options, {validationError: error}));returnfalse;
}
});
If models tend to represent a single row of data, a Backbone Collection is more analogous to a table full of data … or a small slice or page of that table, or a collection of rows that belong together for a particular reason – all of the messages in this particular folder, all of the documents belonging to this particular author, and so on. Collections maintain indexes of their models, both in order, and for lookup by id.
Create a new Collection , perhaps to contain a specific type of model. If a comparator is specified, the Collection will maintain its models in sort order, as they’re added and removed.
varCollection=Backbone.Collection=function(models, options) {
options || (options = {});this.preinitialize.apply(this,arguments);if(options.model)this.model= options.model;if(options.comparator!==void0)this.comparator= options.comparator;this.\_reset();this.initialize.apply(this,arguments);if(models)this.reset(models, _.extend({silent:true}, options));
};
Default options for Collection#set.
varsetOptions = {add:true,remove:true,merge:true};varaddOptions = {add:true,remove:false};
Splices insert into array at index at.
varsplice =function(array, insert, at) {
at =Math.min(Math.max(at,0), array.length);vartail =Array(array.length- at);varlength = insert.length;vari;for(i =0; i < tail.length; i++) tail[i] = array[i + at];for(i =0; i < length; i++) array[i + at] = insert[i];for(i =0; i < tail.length; i++) array[i + length + at] = tail[i];
};
Define the Collection’s inheritable methods.
_.extend(Collection.prototype,Events, {
The default model for a collection is just a Backbone.Model. This should be overridden in most cases.
model:Model,
preinitialize is an empty function by default. You can override it with a function or object. preinitialize will run before any instantiation logic is run in the Collection.
preinitialize:function(){},
Initialize is an empty function by default. Override it with your own initialization logic.
initialize:function(){},
The JSON representation of a Collection is an array of the models’ attributes.
toJSON:function(options) {returnthis.map(function(model) {returnmodel.toJSON(options); });
},
Proxy Backbone.sync by default.
sync:function() {returnBackbone.sync.apply(this,arguments);
},
Add a model, or list of models to the set. models may be Backbone Models or raw JavaScript objects to be converted to Models, or any combination of the two.
add:function(models, options) {returnthis.set(models, _.extend({merge:false}, options, addOptions));
},
Remove a model, or a list of models from the set.
remove:function(models, options) {
options = _.extend({}, options);varsingular = !_.isArray(models);
models = singular ? [models] : models.slice();varremoved =this.\_removeModels(models, options);if(!options.silent&& removed.length) {
options.changes= {added: [],merged: [],removed: removed};this.trigger('update',this, options);
}returnsingular ? removed[0] : removed;
},
Update a collection by set-ing a new list of models, adding new ones, removing models that are no longer present, and merging models that already exist in the collection, as necessary. Similar to Model#set , the core operation for updating the data contained by the collection.
set:function(models, options) {if(models ==null)return;
options = _.extend({}, setOptions, options);if(options.parse&& !this.\_isModel(models)) {
models =this.parse(models, options) || [];
}varsingular = !_.isArray(models);
models = singular ? [models] : models.slice();varat = options.at;if(at !=null) at = +at;if(at >this.length) at =this.length;if(at <0) at +=this.length+1;varset = [];vartoAdd = [];vartoMerge = [];vartoRemove = [];varmodelMap = {};varadd = options.add;varmerge = options.merge;varremove = options.remove;varsort =false;varsortable =this.comparator&& at ==null&& options.sort!==false;varsortAttr = _.isString(this.comparator) ?this.comparator:null;
Turn bare objects into model references, and prevent invalid models from being added.
varmodel, i;for(i =0; i < models.length; i++) {
model = models[i];
If a duplicate is found, prevent it from being added and optionally merge it into the existing model.
varexisting =this.get(model);if(existing) {if(merge && model !== existing) {varattrs =this.\_isModel(model) ? model.attributes: model;if(options.parse) attrs = existing.parse(attrs, options);
existing.set(attrs, options);
toMerge.push(existing);if(sortable && !sort) sort = existing.hasChanged(sortAttr);
}if(!modelMap[existing.cid]) {
modelMap[existing.cid] =true;
set.push(existing);
}
models[i] = existing;
If this is a new, valid model, push it to the toAdd list.
}elseif(add) {
model = models[i] =this.\_prepareModel(model, options);if(model) {
toAdd.push(model);this.\_addReference(model, options);
modelMap[model.cid] =true;
set.push(model);
}
}
}
Remove stale models.
if(remove) {for(i =0; i <this.length; i++) {
model =this.models[i];if(!modelMap[model.cid]) toRemove.push(model);
}if(toRemove.length)this.\_removeModels(toRemove, options);
}
See if sorting is needed, update length and splice in new models.
varorderChanged =false;varreplace = !sortable && add && remove;if(set.length&& replace) {
orderChanged =this.length!== set.length|| _.some(this.models,function(m, index) {returnm !== set[index];
});this.models.length=0;splice(this.models, set,0);this.length=this.models.length;
}elseif(toAdd.length) {if(sortable) sort =true;splice(this.models, toAdd, at ==null?this.length: at);this.length=this.models.length;
}
Silently sort the collection if appropriate.
if(sort)this.sort({silent:true});
Unless silenced, it’s time to fire all appropriate add/sort/update events.
if(!options.silent) {for(i =0; i < toAdd.length; i++) {if(at !=null) options.index= at + i;
model = toAdd[i];
model.trigger('add', model,this, options);
}if(sort || orderChanged)this.trigger('sort',this, options);if(toAdd.length|| toRemove.length|| toMerge.length) {
options.changes= {added: toAdd,removed: toRemove,merged: toMerge
};this.trigger('update',this, options);
}
}
Return the added (or merged) model (or models).
returnsingular ? models[0] : models;
},
When you have more items than you want to add or remove individually, you can reset the entire set with a new list of models, without firing any granular add or remove events. Fires reset when finished. Useful for bulk operations and optimizations.
reset:function(models, options) {
options = options ? _.clone(options) : {};for(vari =0; i <this.models.length; i++) {this.\_removeReference(this.models[i], options);
}
options.previousModels=this.models;this.\_reset();
models =this.add(models, _.extend({silent:true}, options));if(!options.silent)this.trigger('reset',this, options);returnmodels;
},
Add a model to the end of the collection.
push:function(model, options) {returnthis.add(model, _.extend({at:this.length}, options));
},
Remove a model from the end of the collection.
pop:function(options) {varmodel =this.at(this.length-1);returnthis.remove(model, options);
},
Add a model to the beginning of the collection.
unshift:function(model, options) {returnthis.add(model, _.extend({at:0}, options));
},
Remove a model from the beginning of the collection.
shift:function(options) {varmodel =this.at(0);returnthis.remove(model, options);
},
Slice out a sub-array of models from the collection.
slice:function() {returnslice.apply(this.models,arguments);
},
Get a model from the set by id, cid, model object with id or cid properties, or an attributes object that is transformed through modelId.
get:function(obj) {if(obj ==null)returnvoid0;returnthis.\_byId[obj] ||this.\_byId[this.modelId(this.\_isModel(obj) ? obj.attributes: obj, obj.idAttribute)] ||
obj.cid&&this.\_byId[obj.cid];
},
Returns true if the model is in the collection.
has:function(obj) {returnthis.get(obj) !=null;
},
Get the model at the given index.
at:function(index) {if(index <0) index +=this.length;returnthis.models[index];
},
Return models with matching attributes. Useful for simple cases of filter.
where:function(attrs, first) {returnthis[first ?'find':'filter'](attrs);
},
Return the first model with matching attributes. Useful for simple cases of find.
findWhere:function(attrs) {returnthis.where(attrs,true);
},
Force the collection to re-sort itself. You don’t need to call this under normal circumstances, as the set will maintain sort order as each item is added.
sort:function(options) {varcomparator =this.comparator;if(!comparator)thrownewError('Cannot sort a set without a comparator');
options || (options = {});varlength = comparator.length;if(_.isFunction(comparator)) comparator = comparator.bind(this);
Run sort based on type of comparator.
if(length ===1|| _.isString(comparator)) {this.models=this.sortBy(comparator);
}else{this.models.sort(comparator);
}if(!options.silent)this.trigger('sort',this, options);returnthis;
},
Pluck an attribute from each model in the collection.
pluck:function(attr) {returnthis.map(attr +'');
},
Fetch the default set of models for this collection, resetting the collection when they arrive. If reset: true is passed, the response data will be passed through the reset method instead of set.
fetch:function(options) {
options = _.extend({parse:true}, options);varsuccess = options.success;varcollection =this;
options.success=function(resp) {varmethod = options.reset?'reset':'set';
collection[method](resp, options);if(success) success.call(options.context, collection, resp, options);
collection.trigger('sync', collection, resp, options);
};wrapError(this, options);returnthis.sync('read',this, options);
},
Create a new instance of a model in this collection. Add the model to the collection immediately, unless wait: true is passed, in which case we wait for the server to agree.
create:function(model, options) {
options = options ? _.clone(options) : {};varwait = options.wait;
model =this.\_prepareModel(model, options);if(!model)returnfalse;if(!wait)this.add(model, options);varcollection =this;varsuccess = options.success;
options.success=function(m, resp, callbackOpts) {if(wait) {
m.off('error', collection.\_forwardPristineError, collection);
collection.add(m, callbackOpts);
}if(success) success.call(callbackOpts.context, m, resp, callbackOpts);
};
In case of wait:true, our collection is not listening to any of the model’s events yet, so it will not forward the error event. In this special case, we need to listen for it separately and handle the event just once. (The reason we don’t need to do this for the sync event is in the success handler above: we add the model first, which causes the collection to listen, and then invoke the callback that triggers the event.)
if(wait) {
model.once('error',this.\_forwardPristineError,this);
}
model.save(null, options);returnmodel;
},
parse converts a response into a list of models to be added to the collection. The default implementation is just to pass it through.
parse:function(resp, options) {returnresp;
},
Create a new collection with an identical list of models as this one.
clone:function() {returnnewthis.constructor(this.models, { model: this.model, comparator: this.comparator });
},
Define how to uniquely identify models in the collection.
modelId:function(attrs, idAttribute) {returnattrs[idAttribute ||this.model.prototype.idAttribute||'id'];
},
Get an iterator of all models in this collection.
values:function() {returnnewCollectionIterator(this,ITERATOR\_VALUES);
},
Get an iterator of all model IDs in this collection.
keys:function() {returnnewCollectionIterator(this,ITERATOR\_KEYS);
},
Get an iterator of all [ID, model] tuples in this collection.
entries:function() {returnnewCollectionIterator(this,ITERATOR\_KEYSVALUES);
},
Private method to reset all internal state. Called when the collection is first initialized or reset.
\_reset:function() {this.length=0;this.models= [];this.\_byId= {};
},
Prepare a hash of attributes (or other model) to be added to this collection.
\_prepareModel:function(attrs, options) {if(this.\_isModel(attrs)) {if(!attrs.collection) attrs.collection=this;returnattrs;
}
options = options ? _.clone(options) : {};
options.collection=this;varmodel;if(this.model.prototype) {
model =newthis.model(attrs, options);
}else{
ES class methods didn’t have prototype
model =this.model(attrs, options);
}if(!model.validationError)returnmodel;this.trigger('invalid',this, model.validationError, options);returnfalse;
},
Internal method called by both remove and set.
\_removeModels:function(models, options) {varremoved = [];for(vari =0; i < models.length; i++) {varmodel =this.get(models[i]);if(!model)continue;varindex =this.indexOf(model);this.models.splice(index,1);this.length--;
Remove references before triggering ‘remove’ event to prevent an infinite loop. #3693
deletethis.\_byId[model.cid];varid =this.modelId(model.attributes, model.idAttribute);if(id !=null)deletethis.\_byId[id];if(!options.silent) {
options.index= index;
model.trigger('remove', model,this, options);
}
removed.push(model);this.\_removeReference(model, options);
}if(models.length>0&& !options.silent)deleteoptions.index;returnremoved;
},
Method for checking whether an object should be considered a model for the purposes of adding to the collection.
\_isModel:function(model) {returnmodelinstanceofModel;
},
Internal method to create a model’s ties to a collection.
\_addReference:function(model, options) {this.\_byId[model.cid] = model;varid =this.modelId(model.attributes, model.idAttribute);if(id !=null)this.\_byId[id] = model;
model.on('all',this.\_onModelEvent,this);
},
Internal method to sever a model’s ties to a collection.
\_removeReference:function(model, options) {deletethis.\_byId[model.cid];varid =this.modelId(model.attributes, model.idAttribute);if(id !=null)deletethis.\_byId[id];if(this=== model.collection)deletemodel.collection;
model.off('all',this.\_onModelEvent,this);
},
Internal method called every time a model in the set fires an event. Sets need to update their indexes when models change ids. All other events simply proxy through. “add” and “remove” events that originate in other collections are ignored.
\_onModelEvent:function(event, model, collection, options) {if(model) {if((event ==='add'|| event ==='remove') && collection !==this)return;if(event ==='destroy')this.remove(model, options);if(event ==='changeId') {varprevId =this.modelId(model.previousAttributes(), model.idAttribute);varid =this.modelId(model.attributes, model.idAttribute);if(prevId !=null)deletethis.\_byId[prevId];if(id !=null)this.\_byId[id] = model;
}
}this.trigger.apply(this,arguments);
},
Internal callback method used in create. It serves as a stand-in for the _onModelEvent method, which is not yet bound during the wait period of the create call. We still want to forward any 'error' event at the end of the wait period, hence a customized callback.
\_forwardPristineError:function(model, collection, options) {
Prevent double forward if the model was already in the collection before the call to create.
if(this.has(model))return;this.\_onModelEvent('error', model, collection, options);
}
});
Defining an @@iterator method implements JavaScript’s Iterable protocol. In modern ES2015 browsers, this value is found at Symbol.iterator.
/\* global Symbol \*/var$$iterator =typeofSymbol==='function'&&Symbol.iterator;if($$iterator) {Collection.prototype[$$iterator] =Collection.prototype.values;
}
A CollectionIterator implements JavaScript’s Iterator protocol, allowing the use of for of loops in modern browsers and interoperation between Backbone.Collection and other JavaScript functions and third-party libraries which can operate on Iterables.
varCollectionIterator=function(collection, kind) {this.\_collection= collection;this.\_kind= kind;this.\_index=0;
};
This “enum” defines the three possible kinds of values which can be emitted by a CollectionIterator that correspond to the values(), keys() and entries() methods on Collection, respectively.
varITERATOR\_VALUES=1;varITERATOR\_KEYS=2;varITERATOR\_KEYSVALUES=3;
All Iterators should themselves be Iterable.
if($$iterator) {CollectionIterator.prototype[$$iterator] =function() {returnthis;
};
}CollectionIterator.prototype.next=function() {if(this.\_collection) {
Only continue iterating if the iterated collection is long enough.
if(this.\_index<this.\_collection.length) {varmodel =this.\_collection.at(this.\_index);this.\_index++;
Construct a value depending on what kind of values should be iterated.
varvalue;if(this.\_kind===ITERATOR\_VALUES) {
value = model;
}else{varid =this.\_collection.modelId(model.attributes, model.idAttribute);if(this.\_kind===ITERATOR\_KEYS) {
value = id;
}else{// ITERATOR\_KEYSVALUESvalue = [id, model];
}
}return{value: value,done:false};
}
Once exhausted, remove the reference to the collection so future calls to the next method always return done.
this.\_collection=void0;
}return{value:void0,done:true};
};
Backbone Views are almost more convention than they are actual code. A View is simply a JavaScript object that represents a logical chunk of UI in the DOM. This might be a single item, an entire list, a sidebar or panel, or even the surrounding frame which wraps your whole app. Defining a chunk of UI as a View allows you to define your DOM events declaratively, without having to worry about render order … and makes it easy for the view to react to specific changes in the state of your models.
Creating a Backbone.View creates its initial element outside of the DOM, if an existing element is not provided…
varView=Backbone.View=function(options) {this.cid= _.uniqueId('view');this.preinitialize.apply(this,arguments);
_.extend(this, _.pick(options, viewOptions));this.\_ensureElement();this.initialize.apply(this,arguments);
};
Cached regex to split keys for delegate.
vardelegateEventSplitter =/^(\S+)\s\*(.\*)$/;
List of view options to be set as properties.
varviewOptions = ['model','collection','el','id','attributes','className','tagName','events'];
Set up all inheritable Backbone.View properties and methods.
_.extend(View.prototype,Events, {
The default tagName of a View’s element is "div".
tagName:'div',
jQuery delegate for element lookup, scoped to DOM elements within the current view. This should be preferred to global lookups where possible.
$:function(selector) {returnthis.$el.find(selector);
},
preinitialize is an empty function by default. You can override it with a function or object. preinitialize will run before any instantiation logic is run in the View
preinitialize:function(){},
Initialize is an empty function by default. Override it with your own initialization logic.
initialize:function(){},
render is the core function that your view should override, in order to populate its element (this.el), with the appropriate HTML. The convention is for render to always return this.
render:function() {returnthis;
},
Remove this view by taking the element out of the DOM, and removing any applicable Backbone.Events listeners.
remove:function() {this.\_removeElement();this.stopListening();returnthis;
},
Remove this view’s element from the document and all event listeners attached to it. Exposed for subclasses using an alternative DOM manipulation API.
\_removeElement:function() {this.$el.remove();
},
Change the view’s element (this.el property) and re-delegate the view’s events on the new element.
setElement:function(element) {this.undelegateEvents();this.\_setElement(element);this.delegateEvents();returnthis;
},
Creates the this.el and this.$el references for this view using the given el. el can be a CSS selector or an HTML string, a jQuery context or an element. Subclasses can override this to utilize an alternative DOM manipulation API and are only required to set the this.el property.
\_setElement:function(el) {this.$el= elinstanceofBackbone.$? el :Backbone.$(el);this.el=this.$el[0];
},
Set callbacks, where this.events is a hash of
{“event selector”: “callback”}
{
'mousedown .title': 'edit',
'click .button': 'save',
'click .open': function(e) { ... }
}
pairs. Callbacks will be bound to the view, with this set properly. Uses event delegation for efficiency. Omitting the selector binds the event to this.el.
delegateEvents:function(events) {
events || (events = _.result(this,'events'));if(!events)returnthis;this.undelegateEvents();for(varkeyinevents) {varmethod = events[key];if(!_.isFunction(method)) method =this[method];if(!method)continue;varmatch = key.match(delegateEventSplitter);this.delegate(match[1], match[2], method.bind(this));
}returnthis;
},
Add a single event listener to the view’s element (or a child element using selector). This only works for delegate-able events: not focus, blur, and not change, submit, and reset in Internet Explorer.
delegate:function(eventName, selector, listener) {this.$el.on(eventName +'.delegateEvents'+this.cid, selector, listener);returnthis;
},
Clears all callbacks previously bound to the view by delegateEvents. You usually don’t need to use this, but may wish to if you have multiple Backbone views attached to the same DOM element.
undelegateEvents:function() {if(this.$el)this.$el.off('.delegateEvents'+this.cid);returnthis;
},
A finer-grained undelegateEvents for removing a single delegated event. selector and listener are both optional.
undelegate:function(eventName, selector, listener) {this.$el.off(eventName +'.delegateEvents'+this.cid, selector, listener);returnthis;
},
Produces a DOM element to be assigned to your view. Exposed for subclasses using an alternative DOM manipulation API.
\_createElement:function(tagName) {returndocument.createElement(tagName);
},
Ensure that the View has a DOM element to render into. If this.el is a string, pass it through $(), take the first matching element, and re-assign it to el. Otherwise, create an element from the id, className and tagName properties.
\_ensureElement:function() {if(!this.el) {varattrs = _.extend({}, _.result(this,'attributes'));if(this.id) attrs.id= _.result(this,'id');if(this.className) attrs['class'] = _.result(this,'className');this.setElement(this.\_createElement(_.result(this,'tagName')));this.\_setAttributes(attrs);
}else{this.setElement(_.result(this,'el'));
}
},
Set attributes from a hash on this view’s element. Exposed for subclasses using an alternative DOM manipulation API.
\_setAttributes:function(attributes) {this.$el.attr(attributes);
}
});
Proxy Backbone class methods to Underscore functions, wrapping the model’s attributes object or collection’s models array behind the scenes.
collection.filter(function(model) { return model.get(‘age’) > 10 }); collection.each(this.addView);
Function#apply can be slow so we use the method’s arg count, if we know it.
varaddMethod =function(base, length, method, attribute) {switch(length) {case1:returnfunction() {returnbase[method](this[attribute]);
};case2:returnfunction(value) {returnbase[method](this[attribute], value);
};case3:returnfunction(iteratee, context) {returnbase[method](this[attribute],cb(iteratee,this), context);
};case4:returnfunction(iteratee, defaultVal, context) {returnbase[method](this[attribute],cb(iteratee,this), defaultVal, context);
};default:returnfunction() {varargs = slice.call(arguments);
args.unshift(this[attribute]);returnbase[method].apply(base, args);
};
}
};varaddUnderscoreMethods =function(Class, base, methods, attribute) {
_.each(methods,function(length, method) {if(base[method])Class.prototype[method] =addMethod(base, length, method, attribute);
});
};
Support collection.sortBy('attr') and collection.findWhere({id: 1}).
varcb =function(iteratee, instance) {if(_.isFunction(iteratee))returniteratee;if(_.isObject(iteratee) && !instance.\_isModel(iteratee))returnmodelMatcher(iteratee);if(_.isString(iteratee))returnfunction(model) {returnmodel.get(iteratee); };returniteratee;
};varmodelMatcher =function(attrs) {varmatcher = _.matches(attrs);returnfunction(model) {returnmatcher(model.attributes);
};
};
Underscore methods that we want to implement on the Collection. 90% of the core usefulness of Backbone Collections is actually implemented right here:
varcollectionMethods = {forEach:3,each:3,map:3,collect:3,reduce:0,foldl:0,inject:0,reduceRight:0,foldr:0,find:3,detect:3,filter:3,select:3,reject:3,every:3,all:3,some:3,any:3,include:3,includes:3,contains:3,invoke:0,max:3,min:3,toArray:1,size:1,first:3,head:3,take:3,initial:3,rest:3,tail:3,drop:3,last:3,without:0,difference:0,indexOf:3,shuffle:1,lastIndexOf:3,isEmpty:1,chain:1,sample:3,partition:3,groupBy:3,countBy:3,sortBy:3,indexBy:3,findIndex:3,findLastIndex:3};
Underscore methods that we want to implement on the Model, mapped to the number of arguments they take.
varmodelMethods = {keys:1,values:1,pairs:1,invert:1,pick:0,omit:0,chain:1,isEmpty:1};
Mix in each Underscore method as a proxy to Collection#models.
_.each([
[Collection, collectionMethods,'models'],
[Model, modelMethods,'attributes']
],function(config) {varBase= config[0],
methods = config[1],
attribute = config[2];Base.mixin=function(obj) {varmappings = _.reduce(_.functions(obj),function(memo, name) {
memo[name] =0;returnmemo;
}, {});addUnderscoreMethods(Base, obj, mappings, attribute);
};addUnderscoreMethods(Base, _, methods, attribute);
});
Override this function to change the manner in which Backbone persists models to the server. You will be passed the type of request, and the model in question. By default, makes a RESTful Ajax request to the model’s url(). Some possible customizations could be:
setTimeout to batch rapid-fire updates into a single request.Turn on Backbone.emulateHTTP in order to send PUT and DELETE requests as POST, with a _method parameter containing the true HTTP method, as well as all requests with the body as application/x-www-form-urlencoded instead of application/json with the model in a param named model. Useful when interfacing with server-side languages like PHP that make it difficult to read the body of PUT requests.
Backbone.sync=function(method, model, options) {vartype = methodMap[method];
Default options, unless specified.
_.defaults(options || (options = {}), {emulateHTTP:Backbone.emulateHTTP,emulateJSON:Backbone.emulateJSON});
Default JSON-request options.
varparams = {type: type,dataType:'json'};
Ensure that we have a URL.
if(!options.url) {
params.url= _.result(model,'url') ||urlError();
}
Ensure that we have the appropriate request data.
if(options.data==null&& model && (method ==='create'|| method ==='update'|| method ==='patch')) {
params.contentType='application/json';
params.data=JSON.stringify(options.attrs|| model.toJSON(options));
}
For older servers, emulate JSON by encoding the request into an HTML-form.
if(options.emulateJSON) {
params.contentType='application/x-www-form-urlencoded';
params.data= params.data? {model: params.data} : {};
}
For older servers, emulate HTTP by mimicking the HTTP method with _method And an X-HTTP-Method-Override header.
if(options.emulateHTTP&& (type ==='PUT'|| type ==='DELETE'|| type ==='PATCH')) {
params.type='POST';if(options.emulateJSON) params.data.\_method= type;varbeforeSend = options.beforeSend;
options.beforeSend=function(xhr) {
xhr.setRequestHeader('X-HTTP-Method-Override', type);if(beforeSend)returnbeforeSend.apply(this,arguments);
};
}
Don’t process data on a non-GET request.
if(params.type!=='GET'&& !options.emulateJSON) {
params.processData=false;
}
Pass along textStatus and errorThrown from jQuery.
varerror = options.error;
options.error=function(xhr, textStatus, errorThrown) {
options.textStatus= textStatus;
options.errorThrown= errorThrown;if(error) error.call(options.context, xhr, textStatus, errorThrown);
};
Make the request, allowing the user to override any Ajax options.
varxhr = options.xhr=Backbone.ajax(_.extend(params, options));
model.trigger('request', model, xhr, options);returnxhr;
};
Map from CRUD to HTTP for our default Backbone.sync implementation.
varmethodMap = {'create':'POST','update':'PUT','patch':'PATCH','delete':'DELETE','read':'GET'};
Set the default implementation of Backbone.ajax to proxy through to $. Override this if you’d like to use a different library.
Backbone.ajax=function() {returnBackbone.$.ajax.apply(Backbone.$,arguments);
};
Routers map faux-URLs to actions, and fire events when routes are matched. Creating a new one sets its routes hash, if not set statically.
varRouter=Backbone.Router=function(options) {
options || (options = {});this.preinitialize.apply(this,arguments);if(options.routes)this.routes= options.routes;this.\_bindRoutes();this.initialize.apply(this,arguments);
};
Cached regular expressions for matching named param parts and splatted parts of route strings.
varoptionalParam =/\((.\*?)\)/g;varnamedParam =/(\(\?)?:\w+/g;varsplatParam =/\*\w+/g;varescapeRegExp =/[\-{}\[\]+?.,\\\^$|#\s]/g;
Set up all inheritable Backbone.Router properties and methods.
_.extend(Router.prototype,Events, {
preinitialize is an empty function by default. You can override it with a function or object. preinitialize will run before any instantiation logic is run in the Router.
preinitialize:function(){},
Initialize is an empty function by default. Override it with your own initialization logic.
initialize:function(){},
Manually bind a single named route to a callback. For example:
this.route('search/:query/p:num', 'search', function(query, num) {
...
});
route:function(route, name, callback) {if(!_.isRegExp(route)) route =this.\_routeToRegExp(route);if(_.isFunction(name)) {
callback = name;
name ='';
}if(!callback) callback =this[name];varrouter =this;Backbone.history.route(route,function(fragment) {varargs = router.\_extractParameters(route, fragment);if(router.execute(callback, args, name) !==false) {
router.trigger.apply(router, ['route:'+ name].concat(args));
router.trigger('route', name, args);Backbone.history.trigger('route', router, name, args);
}
});returnthis;
},
Execute a route handler with the provided parameters. This is an excellent place to do pre-route setup or post-route cleanup.
execute:function(callback, args, name) {if(callback) callback.apply(this, args);
},
Simple proxy to Backbone.history to save a fragment into the history.
navigate:function(fragment, options) {Backbone.history.navigate(fragment, options);returnthis;
},
Bind all defined routes to Backbone.history. We have to reverse the order of the routes here to support behavior where the most general routes can be defined at the bottom of the route map.
\_bindRoutes:function() {if(!this.routes)return;this.routes= _.result(this,'routes');varroute, routes = _.keys(this.routes);while((route = routes.pop()) !=null) {this.route(route,this.routes[route]);
}
},
Convert a route string into a regular expression, suitable for matching against the current location hash.
\_routeToRegExp:function(route) {
route = route.replace(escapeRegExp,'\\$&')
.replace(optionalParam,'(?:$1)?')
.replace(namedParam,function(match, optional) {returnoptional ? match :'([^/?]+)';
})
.replace(splatParam,'([^?]\*?)');returnnewRegExp('^'+ route +'(?:\\?([\\s\\S]\*))?$');
},
Given a route, and a URL fragment that it matches, return the array of extracted decoded parameters. Empty or unmatched parameters will be treated as null to normalize cross-browser behavior.
\_extractParameters:function(route, fragment) {varparams = route.exec(fragment).slice(1);return_.map(params,function(param, i) {
Don’t decode the search params.
if(i === params.length-1)returnparam ||null;returnparam ?decodeURIComponent(param) :null;
});
}
});
Handles cross-browser history management, based on either pushState and real URLs, or onhashchange and URL fragments. If the browser supports neither (old IE, natch), falls back to polling.
varHistory=Backbone.History=function() {this.handlers= [];this.checkUrl=this.checkUrl.bind(this);
Ensure that History can be used outside of the browser.
if(typeofwindow!=='undefined') {this.location=window.location;this.history=window.history;
}
};
Cached regex for stripping a leading hash/slash and trailing space.
varrouteStripper =/^[#\/]|\s+$/g;
Cached regex for stripping leading and trailing slashes.
varrootStripper =/^\/+|\/+$/g;
Cached regex for stripping urls of hash.
varpathStripper =/#.\*$/;
Has the history handling already been started?
History.started=false;
Set up all inheritable Backbone.History properties and methods.
_.extend(History.prototype,Events, {
The default interval to poll for hash changes, if necessary, is twenty times a second.
interval:50,
Are we at the app root?
atRoot:function() {varpath =this.location.pathname.replace(/[^\/]$/,'$&/');returnpath ===this.root&& !this.getSearch();
},
Does the pathname match the root?
matchRoot:function() {varpath =this.decodeFragment(this.location.pathname);varrootPath = path.slice(0,this.root.length-1) +'/';returnrootPath ===this.root;
},
Unicode characters in location.pathname are percent encoded so they’re decoded for comparison. %25 should not be decoded since it may be part of an encoded parameter.
decodeFragment:function(fragment) {returndecodeURI(fragment.replace(/%25/g,'%2525'));
},
In IE6, the hash fragment and search params are incorrect if the fragment contains ?.
getSearch:function() {varmatch =this.location.href.replace(/#.\*/,'').match(/\?.+/);returnmatch ? match[0] :'';
},
Gets the true hash value. Cannot use location.hash directly due to bug in Firefox where location.hash will always be decoded.
getHash:function(window) {varmatch = (window||this).location.href.match(/#(.\*)$/);returnmatch ? match[1] :'';
},
Get the pathname and search params, without the root.
getPath:function() {varpath =this.decodeFragment(this.location.pathname+this.getSearch()
).slice(this.root.length-1);returnpath.charAt(0) ==='/'? path.slice(1) : path;
},
Get the cross-browser normalized URL fragment from the path or hash.
getFragment:function(fragment) {if(fragment ==null) {if(this.\_usePushState|| !this.\_wantsHashChange) {
fragment =this.getPath();
}else{
fragment =this.getHash();
}
}returnfragment.replace(routeStripper,'');
},
Start the hash change handling, returning true if the current URL matches an existing route, and false otherwise.
start:function(options) {if(History.started)thrownewError('Backbone.history has already been started');History.started=true;
Figure out the initial configuration. Do we need an iframe? Is pushState desired … is it available?
this.options= _.extend({root:'/'},this.options, options);this.root=this.options.root;this.\_trailingSlash=this.options.trailingSlash;this.\_wantsHashChange=this.options.hashChange!==false;this.\_hasHashChange='onhashchange'inwindow&& (document.documentMode===void0||document.documentMode>7);this.\_useHashChange=this.\_wantsHashChange&&this.\_hasHashChange;this.\_wantsPushState= !!this.options.pushState;this.\_hasPushState= !!(this.history&&this.history.pushState);this.\_usePushState=this.\_wantsPushState&&this.\_hasPushState;this.fragment=this.getFragment();
Normalize root to always include a leading and trailing slash.
this.root= ('/'+this.root+'/').replace(rootStripper,'/');
Transition from hashChange to pushState or vice versa if both are requested.
if(this.\_wantsHashChange&&this.\_wantsPushState) {
If we’ve started off with a route from a pushState-enabled browser, but we’re currently in a browser that doesn’t support it…
if(!this.\_hasPushState&& !this.atRoot()) {varrootPath =this.root.slice(0, -1) ||'/';this.location.replace(rootPath +'#'+this.getPath());
Return immediately as browser will do redirect to new url
returntrue;
Or if we’ve started out with a hash-based route, but we’re currently in a browser where it could be pushState-based instead…
}elseif(this.\_hasPushState&&this.atRoot()) {this.navigate(this.getHash(), {replace:true});
}
}
Proxy an iframe to handle location events if the browser doesn’t support the hashchange event, HTML5 history, or the user wants hashChange but not pushState.
if(!this.\_hasHashChange&&this.\_wantsHashChange&& !this.\_usePushState) {this.iframe=document.createElement('iframe');this.iframe.src='javascript:0';this.iframe.style.display='none';this.iframe.tabIndex= -1;varbody =document.body;
Using appendChild will throw on IE < 9 if the document is not ready.
variWindow = body.insertBefore(this.iframe, body.firstChild).contentWindow;
iWindow.document.open();
iWindow.document.close();
iWindow.location.hash='#'+this.fragment;
}
Add a cross-platform addEventListener shim for older browsers.
varaddEventListener =window.addEventListener||function(eventName, listener) {returnattachEvent('on'+ eventName, listener);
};
Depending on whether we’re using pushState or hashes, and whether ‘onhashchange’ is supported, determine how we check the URL state.
if(this.\_usePushState) {addEventListener('popstate',this.checkUrl,false);
}elseif(this.\_useHashChange&& !this.iframe) {addEventListener('hashchange',this.checkUrl,false);
}elseif(this.\_wantsHashChange) {this.\_checkUrlInterval=setInterval(this.checkUrl,this.interval);
}if(!this.options.silent)returnthis.loadUrl();
},
Disable Backbone.history, perhaps temporarily. Not useful in a real app, but possibly useful for unit testing Routers.
stop:function() {
Add a cross-platform removeEventListener shim for older browsers.
varremoveEventListener =window.removeEventListener||function(eventName, listener) {returndetachEvent('on'+ eventName, listener);
};
Remove window listeners.
if(this.\_usePushState) {removeEventListener('popstate',this.checkUrl,false);
}elseif(this.\_useHashChange&& !this.iframe) {removeEventListener('hashchange',this.checkUrl,false);
}
Clean up the iframe if necessary.
if(this.iframe) {document.body.removeChild(this.iframe);this.iframe=null;
}
Some environments will throw when clearing an undefined interval.
if(this.\_checkUrlInterval)clearInterval(this.\_checkUrlInterval);History.started=false;
},
Add a route to be tested when the fragment changes. Routes added later may override previous routes.
route:function(route, callback) {this.handlers.unshift({route: route,callback: callback});
},
Checks the current URL to see if it has changed, and if it has, calls loadUrl, normalizing across the hidden iframe.
checkUrl:function(e) {varcurrent =this.getFragment();
If the user pressed the back button, the iframe’s hash will have changed and we should use that for comparison.
if(current ===this.fragment&&this.iframe) {
current =this.getHash(this.iframe.contentWindow);
}if(current ===this.fragment) {if(!this.matchRoot())returnthis.notfound();returnfalse;
}if(this.iframe)this.navigate(current);this.loadUrl();
},
Attempt to load the current URL fragment. If a route succeeds with a match, returns true. If no defined routes matches the fragment, returns false.
loadUrl:function(fragment) {
If the root doesn’t match, no routes can match either.
if(!this.matchRoot())returnthis.notfound();
fragment =this.fragment=this.getFragment(fragment);return_.some(this.handlers,function(handler) {if(handler.route.test(fragment)) {
handler.callback(fragment);returntrue;
}
}) ||this.notfound();
},
When no route could be matched, this method is called internally to trigger the 'notfound' event. It returns false so that it can be used in tail position.
notfound:function() {this.trigger('notfound');returnfalse;
},
Save a fragment into the hash history, or replace the URL state if the ‘replace’ option is passed. You are responsible for properly URL-encoding the fragment in advance.
The options object can contain trigger: true if you wish to have the route callback be fired (not usually desirable), or replace: true, if you wish to modify the current URL without adding an entry to the history.
navigate:function(fragment, options) {if(!History.started)returnfalse;if(!options || options ===true) options = {trigger: !!options};
Normalize the fragment.
fragment =this.getFragment(fragment ||'');
Strip trailing slash on the root unless _trailingSlash is true
varrootPath =this.root;if(!this.\_trailingSlash&& (fragment ===''|| fragment.charAt(0) ==='?')) {
rootPath = rootPath.slice(0, -1) ||'/';
}varurl = rootPath + fragment;
Strip the fragment of the query and hash for matching.
fragment = fragment.replace(pathStripper,'');
Decode for matching.
vardecodedFragment =this.decodeFragment(fragment);if(this.fragment=== decodedFragment)return;this.fragment= decodedFragment;
If pushState is available, we use it to set the fragment as a real URL.
if(this.\_usePushState) {this.history[options.replace?'replaceState':'pushState']({},document.title, url);
If hash changes haven’t been explicitly disabled, update the hash fragment to store history.
}elseif(this.\_wantsHashChange) {this.\_updateHash(this.location, fragment, options.replace);if(this.iframe&& fragment !==this.getHash(this.iframe.contentWindow)) {variWindow =this.iframe.contentWindow;
Opening and closing the iframe tricks IE7 and earlier to push a history entry on hash-tag change. When replace is true, we don’t want this.
if(!options.replace) {
iWindow.document.open();
iWindow.document.close();
}this.\_updateHash(iWindow.location, fragment, options.replace);
}
If you’ve told us that you explicitly don’t want fallback hashchange- based history, then navigate becomes a page refresh.
}else{returnthis.location.assign(url);
}if(options.trigger)returnthis.loadUrl(fragment);
},
Update the hash location, either replacing the current entry, or adding a new one to the browser history.
\_updateHash:function(location, fragment, replace) {if(replace) {varhref = location.href.replace(/(javascript:|#).\*$/,'');
location.replace(href +'#'+ fragment);
}else{
Some browsers require that hash contains a leading #.
location.hash='#'+ fragment;
}
}
});
Create the default Backbone.history.
Backbone.history=newHistory;
Helper function to correctly set up the prototype chain for subclasses. Similar to goog.inherits, but uses a hash of prototype properties and class properties to be extended.
varextend =function(protoProps, staticProps) {varparent =this;varchild;
The constructor function for the new subclass is either defined by you (the “constructor” property in your extend definition), or defaulted by us to simply call the parent constructor.
if(protoProps && _.has(protoProps,'constructor')) {
child = protoProps.constructor;
}else{
child =function(){returnparent.apply(this,arguments); };
}
Add static properties to the constructor function, if supplied.
_.extend(child, parent, staticProps);
Set the prototype chain to inherit from parent, without calling parent‘s constructor function and add the prototype properties.
child.prototype= _.create(parent.prototype, protoProps);
child.prototype.constructor= child;
Set a convenience property in case the parent’s prototype is needed later.
child.\_\_super\_\_= parent.prototype;returnchild;
};
Set up inheritance for the model, collection, router, view and history.
Model.extend=Collection.extend=Router.extend=View.extend=History.extend= extend;
Throw an error when a URL is needed, and none is supplied.
varurlError =function() {thrownewError('A "url" property or function must be specified');
};
Wrap an optional error callback with a fallback error event.
varwrapError =function(model, options) {varerror = options.error;
options.error=function(resp) {if(error) error.call(options.context, model, resp, options);
model.trigger('error', model, resp, options);
};
};
Provide useful information when things go wrong. This method is not meant to be used directly; it merely provides the necessary introspection for the external debugInfo function.
Backbone.\_debug=function() {return{root: root,\_: _};
};returnBackbone;
});