import Repl from '@/repl/Repl.tsx'; import CodeLink from '@/mdx-components/CodeLink.tsx';

OrderedMap

A type of Map that maintains the order of iteration according to when entries were set.

<Signature code={type OrderedMap<K, V> extends Map<K, V>} />

The iteration behavior of OrderedMap is the same as native ES6 Map and JavaScript Object.

Note that OrderedMap are more expensive than non-ordered Map and may consume more memory. OrderedMap#set is amortized O(log32 N), but not stable.

Let's look at the following example to see the difference between Map and OrderedMap:

<Repl defaultValue={Map({a: 1, c: 3, b: 2})} />

The b key is re-located on the second position.

<Repl defaultValue={OrderedMap({a: 1, c: 3, b: 2})} />

The b key is still on the third position.

Similar API with Map

OrderedMap has the exact same API as Map. The only new method is <CodeLink to="isOrderedMap">OrderedMap.isOrderedMap(maybeOrderedMap)</CodeLink> to check if a value is an OrderedMap.

Construction

<MemberLabel label="OrderedMap()" />

Creates a new Immutable OrderedMap.

<Signature code={OrderedMap<K, V>(collection?: Iterable<[K, V]>): OrderedMap<K, V> OrderedMap<V>(obj: { [key: PropertyKey]: V }): OrderedMap<PropertyKey, V>} />

Note: OrderedMap is a factory function and not a class, and does not use the new keyword during construction.

<Repl defaultValue={OrderedMap({ a: 1, b: 2 })} />

Static Methods

<MemberLabel label="OrderedMap.isOrderedMap()" />

True if the provided value is an OrderedMap.

<Signature code={OrderedMap.isOrderedMap(maybeOrderedMap): boolean} />