Errors

Mobile JSON Wire Protocol Errors

This package exports a number of classes and methods related to Selenium error handling. There are error classes for each Selenium error type (see here, as well as the context errors in the mobile spec).

These classes, which are constructed with a string message (defaulting to the "Details" below), are available through the errors object exported by the module. They are

Code	Class Name	Details
	MJSONWPError<sup>1</sup>	Base class for other errors
6	NoSuchDriverError	A session is either terminated or not started
7	NoSuchElementError	An element could not be located on the page using the given search parameters
8	NoSuchFrameError	A request to switch to a frame could not be satisfied because the frame could not be found
9	UnknownCommandError	The requested resource could not be found, or a request was received using an HTTP method that is not supported by the mapped resource
10	StaleElementReferenceError	An element command failed because the referenced element is no longer attached to the DOM
11	ElementNotVisibleError	An element command could not be completed because the element is not visible on the page
12	InvalidElementStateError	An element command could not be completed because the element is in an invalid state (e.g., attempting to click a disabled element)
13	UnknownError	An unknown server-side error occurred while processing the command
405	NotYetImplementedError	The operation requested is not yet implemented by the driver
405	NotImplementedError	The operation requested will not be implemented by the driver
15	ElementIsNotSelectableError	An attempt was made to select an element that cannot be selected
17	JavaScriptError	An error occurred while executing user supplied JavaScript
19	XPathLookupError	An error occurred while searching for an element by XPath
21	TimeoutError	An operation did not complete before its timeout expired
23	NoSuchWindowError	A request to switch to a different window could not be satisfied because the window could not be found
24	InvalidCookieDomainError	An illegal attempt was made to set a cookie under a different domain than the current page
25	UnableToSetCookieError	A request to set a cookie's value could not be satisfied
26	UnexpectedAlertOpenError	A modal dialog was open, blocking this operation
27	NoAlertOpenError	An attempt was made to operate on a modal dialog when one was not open
28	ScriptTimeoutError	A script did not complete before its timeout expired
29	InvalidElementCoordinatesError	The coordinates provided to an interactions operation are invalid
30	IMENotAvailableError	Input Method Editor was not available
31	IMEEngineActivationFailedError	An Input Method Editor engine could not be started
32	InvalidSelectorError	Argument was an invalid selector (e.g., XPath/CSS)
33	SessionNotCreatedError	A new session could not be created
34	MoveTargetOutOfBoundsError	Target provided for a move action is out of bounds
35	NoSuchContextError	Context provided (e.g., WEBVIEW_42) does not exist
36	InvalidContextError	The operation could not be performed in the current context
	BadParametersError<sup>2</sup>	The parameters specified for the operation are incorrect

¹ MJSONWPError is the base class for all errors that are part of the Selenium specification (i.e., all errors except BadParametersError), and not itself part of that specification. ² BadParametersError is not part of the Selenium specification, but deals with request management.

There are, in addition, two helper methods for dealing with errors

isErrorType (err, type)

• checks if the err object is a Mobile JSON Wire Protocol error of a particular type
• arguments
  • err - the error object to test
  • type - the error class to test against
• usage
  jsCopy

  import { errors, isErrorType } from 'appium-base-driver';
  
  try {
    // do some stuff...
  } catch (err) {
    if (isErrorType(err, errors.InvalidCookieDomainError)) {
      // process...
    }
  }
  

errorFromCode (code, message)

• retrieve the appropriate error for an error code, with the supplied message.
• arguments
  • code - the integer error code for a Mobile JSON Wire Protocol error
  • message - the message to be encapsulated in the error
• usage
  jsCopy

  import { errors, errorFromCode } from 'appium-base-driver';
  
  let error = errorFromCode(6, 'an error has occurred');
  
  console.log(error instanceof errors.NoSuchDriverError);
  // => true
  
  console.log(error.message === 'an error has occurred');
  // => true