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.
WeakIdentityMap is based on Map, WeakRef and FinalizationRegistry objects.
- No dependencies
- TypeScript
- ES2021
- Node.js >=14.6.0
npm i weak-identity-map
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');Returns the number of values in the WeakIdentityMap object.
The set() method adds or updates an element with a specified key and an object to a WeakIdentityMap object.
The get() method returns a reference to a specified object from a WeakIdentityMap object.
The has() method returns a boolean indicating whether an object with the specified key exists or not.
The delete() method removes the specified object from a WeakIdentityMap object by key.
The keys() method returns a new Iterator object that contains the keys for each element in the WeakIdentityMap object in insertion order.
The entries() method returns a new Iterator object that contains the [key, value] pairs for each element in the WeakIdentityMap object in insertion order.
The values() method returns a new Iterator object that contains the values for each element in the WeakIdentityMap object in insertion order.
The forEach() method executes a provided function once per each key/value pair in the WeakIdentityMap object, in insertion order.
The clear() method removes all elements from a WeakIdentityMap object.
WeakIdentityMap is MIT licensed.