preallocating Array

JavaScript performance comparison

Revision 9 of this test case created by sutekidayo

Preparation code

<script>
  var N = 10000;
</script>
    

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Testing in CCBot 2.0.0 / Other 0.0.0
Test Ops/sec
new Array
var a = [];
for (var i = 0; i < N; ++i) {
 a.push("foo");
}
pending…
new Array(N) and length
var a = new Array(N);
a.length = 0;
for (var i = 0; i < N; ++i) {
 a.push("foo");
}
pending…
new Array(N) and fill without shortening
var a = new Array(N);
for (var i = 0; i < N; ++i) {
 a[i] = "foo";
}
pending…
new Array(N) and push adapter
var b = new Array(N);
a = {
 i: 0,
 push: function(x) {
  b[this.i++] = x;
 }
};
for (var i = 0; i < N; ++i) {
 a.push("foo");
}
pending…
new Array with Length
var a = [];
a.length = N;
for (var i = 0; i < N; ++i) {
 a[i] = "foo";
}
pending…

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Revisions

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