CODEWITHSUNDEEP
javascriptarrays
Anand Joshi
Anand Joshi

Reputation: 454

How does Javascript associative array work?

I am in bit of a puzzle, recently I had worked on a project where use of javascript was necessary. Everything is working fine I just need to know how does it work

eg : I had a dynamic variable count, which use to get some value, lets say I get the value as var count = 6;

Now when I put this in array {count : count } I get the output as {count : 6}

Now my doubt is the output should have been { 6 : 6} as count should have been replaced with its value but it didn't happen so. Why is happening ? and how is this working properly ?

Upvotes: 0

Views: 43

Answers (3)

Zaenille
Zaenille

Reputation: 1384

In JavaScript associative arrays (or most associative arrays for that matter), the left side is the key, and the right side is the value. -> {key:value}

When you put {count:count} when you have a count variable beforehand (let's say its value is 10), what will happen is it will be read as {count:10}.

The left-hand side, or the key, is not a variable, but a constant.

Upvotes: 0

mystery
mystery

Reputation: 19523

The JavaScript object initialisation syntax lets you use bare words. If you do this:

{ foo: 6, bar: 12 }

It's equivalent to this:

{ 'foo': 6, 'bar': 12 }

What you want is to assign directly, like so:

var foobar = {};
foobar[foo] = 6;
foobar[bar] = 12;

Upvotes: 0

ColBeseder
ColBeseder

Reputation: 3669

The key value pairs treat the key as a literal and the value as a variable.

so:

var count = 6;
var o = {count: count};  // results in {count: 6}

but to use a variable as the key, you can do this:

var count = 6;
var o = {};
o[count] = count;  // results in: {6: 6}

Upvotes: 1

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