create sparse array

JavaScript performance comparison

Test case created by kerryChen95

Preparation code

function arrayConstructor (i, length) {
  var arr;
  while(i--) {
    arr = new Array(length);
  return arr;
function modifyArrayLength (i, length) {
  var arr;
  while(i--) {
    arr = [];
    arr.length = length;
  return arr;

var loopCount = 10000;
var longLength = 1000;
var shortLength = 5;

arrayConstructor(loopCount, longLength).length === longLength || alert('arrayConstructor broken');
modifyArrayLength(loopCount, longLength).length === longLength || alert('modifyArrayLength broken');

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Testing in unknown unknown
Test Ops/sec
array constructor
arrayConstructor(loopCount, longLength);
arrayConstructor(loopCount, shortLength);
modify array length
modifyArrayLength(loopCount, longLength);
modifyArrayLength(loopCount, shortLength);

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