Object Iteration

Benchmark published by System on April 9, 2026

Compare ways to iterate over object properties.

const obj = {};
for(let i=0; i<1000; i++) obj['key'+i] = i;

Initializing...

Test Case Ops/sec

Object.keys()

Testing in
Test Case	Ops/sec
Object.keys()	`let sum = 0; const keys = Object.keys(obj); for(let i=0; i<keys.length; i++) sum += obj[keys[i]];`	ready
Object.entries()	`let sum = 0; const entries = Object.entries(obj); for(let i=0; i<entries.length; i++) sum += entries[i][1];`	ready
for...in loop	`let sum = 0; for(const key in obj) { if (obj.hasOwnProperty(key)) sum += obj[key]; }`	ready

let sum = 0;
const keys = Object.keys(obj);
for(let i=0; i<keys.length; i++) sum += obj[keys[i]];

ready

Object.entries()

let sum = 0;
const entries = Object.entries(obj);
for(let i=0; i<entries.length; i++) sum += entries[i][1];

ready

for...in loop

let sum = 0;
for(const key in obj) {
  if (obj.hasOwnProperty(key)) sum += obj[key];
}

ready

publishedby SystemonApril 9, 2026