Array extending: push vs concat

JavaScript performance comparison

Revision 5 of this test case created by Jon

Info

Compares techniques for extending an array with another array.

See http://stackoverflow.com/questions/1374126/how-to-append-an-array-to-an-existing-javascript-array

Preparation code

<script>
/**
 * extend an array with another array. See http://stackoverflow.com/a/1374131/1280629
 **/

Array.prototype.extend_push_apply = function(array) {
    this.push.apply(this, array)
}

Array.prototype.extend_for_loop = function(array) {
    for (var i = 0, len = array.length; i < len; ++i) {
        this.push(array[i]);
    };    
}

Array.prototype.extend_forEach = function (array) {
    array.forEach(function(x) {this.push(x)}, this);    
}

Array.prototype.extend_splice = function (array) {
    array.unshift(array.length)
    array.unshift(this.length)
    Array.prototype.splice.apply(this,array)
    array.shift() // restore b
    array.shift() //
}

var short_array = []
short_array.length = 10000;
</script>
<script>
Benchmark.prototype.setup = function() {
    var array_to_extend = [];
};
</script>

Test runner

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Testing in unknown unknown
Test Ops/sec
Extend via push apply
array_to_extend.extend_push_apply(short_array);
pending…
Extend via splice
array_to_extend.extend_splice(short_array);
pending…
Extend via push for loop
array_to_extend.extend_for_loop(short_array);
pending…
Extend via push forEach
array_to_extend.extend_forEach(short_array);
pending…

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