The WeakIdentityMap object holds key-value pairs of weakly referenced objects and remembers the original insertion order of the keys
npm install weak-identity-map
The WeakIdentityMap object holds key-value pairs of weakly referenced objects and remembers the original insertion order of the keys.
A weak reference to an object is a reference that does not prevent the object from being reclaimed by the garbage collector. In contrast, a normal (or strong) reference keeps an object in memory.
> Identity Map ensures that each object gets loaded only once by keeping every loaded object in a map. Looks up objects using the map when referring to them.
>
> – Martin Fowler
WeakIdentityMap is based on Map, WeakRef and FinalizationRegistry objects.
- No dependencies
- TypeScript
- ES2021
- Node.js >=14.6.0
``
npm i weak-identity-map
`javascript
const map = new WeakIdentityMap();
let entity = {};
map.set('key', entity);
// returns a reference to the entity
map.get('key');
entity = null;
// ...
// GC reclaims space
// ...
// returns undefined
map.get('key');
`
#### size: number
Returns the number of values in the WeakIdentityMap object.
#### set(any, object): this
The set() method adds or updates an element with a specified key and an object to a WeakIdentityMap object.
#### get(any): object | undefined
The get() method returns a reference to a specified object from a WeakIdentityMap object.
#### has(any): boolean
The has() method returns a boolean indicating whether an object with the specified key exists or not.
#### delete(any): boolean
The delete() method removes the specified object from a WeakIdentityMap object by key.
#### keys(): IterableIterator\
The keys() method returns a new Iterator object that contains the keys for each element in the WeakIdentityMap object in insertion order.
#### entries(): IterableIterator\<\[any, object\]\>
The entries() method returns a new Iterator object that contains the [key, value] pairs for each element in the WeakIdentityMap object in insertion order.
#### values(): IterableIterator\
The values() method returns a new Iterator object that contains the values for each element in the WeakIdentityMap object in insertion order.
#### forEach(cb): void
The forEach() method executes a provided function once per each key/value pair in the WeakIdentityMap object, in insertion order.
#### clear(): void
The clear() method removes all elements from a WeakIdentityMap` object.
WeakIdentityMap is MIT licensed.