How to set hash key dynamically in javascript

Question

With this code,

h = {}
for (var i in [0,1]){ h[i.ToString] = i; }

I expected same result with h["1"] = 1 and h["2"] = 2.

Why is this code doesn't work, and how can I define hash key dynamically in javascript?

Tim · Accepted Answer · 2014-04-21 10:29:32Z

1

The for .. in loop in JS iterates over keys, not over values (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/for...in). So in your case, you iterate over the keys of the array you have in there.
Those will be 0, 1, 2 ... no matter what you put in there.

What you could do instead would be something like this:

var obj = {};
var data = [1,2,3,4];
data.forEach(function(val) {
    obj[val] = val;
});

answered Apr 21, 2014 at 10:29

Tim

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