Info

Original discussion at http://stackoverflow.com/questions/1232040/how-to-empty-an-array-in-javascript.

This version of the test is much slower because it needs to copy the pre-populated array in each iteration. I have included a control snippet to calculate the time needed for the copy.

Preparation code

 
<script>
  Benchmark.prototype.setup = function() {
    var small = [],
        medium = [],
        big = [],
        smallSize = 100,
        mediumSize = 10000,
        bigSize = 100000;
    
    while (smallSize--) {
        small.push(Math.random());
    }
    
    while (mediumSize--) {
        medium.push(Math.random());
    }
    
    while (bigSize--) {
        big.push(Math.random());
    }
  };
</script>

Test runner

Warning! For accurate results, please disable Firebug before running the tests. (Why?)

Java applet disabled.

small.slice();

medium.slice();

big.slice();

var arr = small.slice();
arr = [];

var arr = medium.slice();
arr = [];

var arr = big.slice();
arr = [];

var arr = small.slice();
arr.length = 0;

var arr = medium.slice();
arr.length = 0;

var arr = big.slice();
arr.length = 0;

var arr = small.slice();
arr.splice(0, arr.length);

var arr = medium.slice();
arr.splice(0, arr.length);

var arr = big.slice();
arr.splice(0, arr.length);

var arr = small.slice();
while(arr.length > 0) {
    arr.pop();
}

var arr = medium.slice();
while(arr.length > 0) {
    arr.pop();
}

var arr = big.slice();
while(arr.length > 0) {
    arr.pop();
}

You can edit these tests or add even more tests to this page by appending /edit to the URL.

Compare results of other browsers

0 comments