Getting the length of a 'named' array?

2018-06-09 01:32:03

This question already has an answer here:

Length of a JavaScript object 32 answers

You could use Object.keys() to obtain an array of keys, then count them:

Object.keys(array).length

Or, if you're targeting ECMAScript 3 or otherwise don't have Object.keys() , then you can count the keys manually:

var length = 0;
for (var key in array) {
    if (array.hasOwnProperty(key)) {
        ++length;
    }
}

There are a few edge cases with this approach though, depending on the browsers you're targeting, so using Mozilla's polyfill for Object.keys() instead might be a good idea.

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