Collections
ES6 introduces four data structures-Map
, WeakMap
, Set
, and WeakSet
. JavaScript, when compared to other languages such as Python and Ruby, had a very weak standard library to support hash or Map data structures or dictionaries. Several hacks were invented to somehow achieve the behavior of a Map
by mapping a string key with an object. There were side effects of such hacks. Language support for such data structures was sorely needed.
ES6 supports standard dictionary data structures; we will look at more details around these in the next section.
Map
Map
allows arbitrary values as keys
. The keys
are mapped to values. Maps allow fast access to values. Let's look at some examples of maps:
const m = new Map(); //Creates an empty Map m.set('first', ...
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