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What is the most efficient way to empty a plain object in javascript?

rated 0 times [ 33] [ 3] / answers: 1 / hits: 23191 / 12 Years ago, sun, march 3, 2013, 12:00:00

As stated Here, It seems that the most efficient way to empty an existing array (and NOT to allocate a new one) in javascript is to use:

array.length = 0;

Does the same operation work for plain objects? (aka associative arrays or dictionaries)
If not, what is the most efficient way to empty an existing javascript object?

I think that allocating a new one is not the best option, since it will push some extra work to the garbage collector, and will allocate some new memory on the heap, but I might be wrong.

I need a solution that works at least with Chrome and Firefox.

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mitchellg

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answered 12 Years ago jaylanw · Accepted Answer

The shortest way to do that is to create a new object. You'd end up garbage collecting all the properties anyway.

var foo = {

    a: 5,

    b: 4

};

foo = {};

You could also iterate over the properties and remove them individually:

for (var prop in foo) {

    if (foo.hasOwnProperty(prop)) {

        delete foo[prop];

    }

}

It's also worth pointing out, as a matter of verbiage, that JavaScript has objects with properties, not associative arrays.