Hashtable vs objects In javascript

Question

I’m new to data structure and I’m learning it in Javascript.

My Question is: Why do we need hash tables when we 've objects in javascript? Can anybody give me a situation where hash tables will be more useful than objects?

https://stackoverflow.com/a/1143522/4051471 – shrys Jul 05 '19 at 06:52 — shrys, Jul 05 '19 at 06:52

score 12 · Accepted Answer · answered Jul 05 '19 at 06:53

"Hashtable" is called different things in different languages. Java has Hashtable and HashMap, Ruby has Hash, Python has dict... in JavaScript, it's called Map.

Objects' keys are limited to strings; Map keys can be anything.

Objects support inheritance; a Map only contains what is specifically put into it.

score 4 · Answer 2 · edited Jul 13 '19 at 07:25

4

Think you means Map instead of HashTable. IMHO Map may be more useful and perform better if you need one of that:

keep order of insertions of key/value pairs;
frequent additional and removal;
key which not String/Symbol.

I think you can obtain more information at MDN

edited Jul 13 '19 at 07:25

marc_s

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answered Jul 05 '19 at 07:06

Vasyl Moskalov

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score 0 · Answer 3 · answered Jul 05 '19 at 07:10

The MDN docs on this are quite helpful: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Map#Objects_and_maps_compared

Most notably, using a map gives you the advantage of using anything as a key, maps retain order, and may perform better when constantly adding and removing values.

Hashtable vs objects In javascript

3 Answers3