Why do we need weakMaps in Javascript?
The WeakMap object is a collection of key/value pairs in which the keys are weakly referenced. The keys must be objects and the values can be arbitrary values.
According to wikipedia, Weak reference is a reference that does not protect the referenced object from collection by a garbage collector, unlike a strong reference. An object referenced only by weak references – meaning "every chain of references that reaches the object includes at least one weak reference as a link" – is considered weakly reachable, and can be treated as unreachable and so may be collected at any time.
Some use cases that would otherwise cause a memory leak which can be worked around using weak maps −
Keeping private data about a specific object and only giving access to it to people with a reference to the Map.
Keeping data about library objects without changing them or incurring overhead.
Keeping data about a small set of objects where many objects of the type exist to not incur problems with hidden classes JS engines use for objects of the same type.
Keeping data about host objects like DOM nodes in the browser.
Adding a capability to an object from the outside.
Published on 16-Sep-2019 12:23:59
