Run details:
Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36
Chrome 91
Linux
Desktop
3 years ago
Test name Executions per second
for-in 1284.5 Ops/sec
Object.keys 494.1 Ops/sec
Script Preparation code:
AخA
 
var obj = {
  'a': 1,
  'b': 1,
  'c': 1,
  'd': 1,
  'e': 1,
  'f': 1,
  'g': 1
};
Tests:
  • for-in

     
    for (var i=10000; i > 0; i--) {
      var k = 0;
      for (var key in obj) {
         k++; 
      }
    }
  • Object.keys

     
    for (var i=10000; i > 0; i--) {
      Object.keys(obj).length;
    }