Declaring variables inside loops

JavaScript performance comparison

Test case created by Shane O'Sullivan

Info

Tests whether declaring a variable inside a loop, rather than declaring outside and just assigning values, is more performant

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Test Ops/sec
Declare in a loop
 
for (var i = 0; i < 1000; i++) {
  var x = 1;
  var y = 2;
  var z = {};
  var a = {};
}
 pending…
Declare outside loop
 
var x, y, z, a, i;
for (i = 0; i < 1000; i++) {
  x = 1;
  y = 2;
  z = {};
  a = {};
}
 pending…

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