MeasureThat.net

Run results for: Performance of JavaScript .forEach, for in v3

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Run details:
Mozilla/5.0 (X11; Linux x86_64; rv:128.0) Gecko/20100101 Firefox/128.0
Firefox 128
Linux
Desktop
2 months ago
Test name Executions per second
.forEach destructured 5.9 Ops/sec
for..of destructured 6.1 Ops/sec
.forEach 6.3 Ops/sec
for..of 6.0 Ops/sec
Script Preparation code:
AخA
 
function generateTestArray() {
  const result = [];
  for (let i = 0; i < 1000000; ++i) {
    result.push({
      a: i,
      b: i / 2,
      r: 0,
    });
  }
  return result;
}
Tests:

  • .forEach destructured

     
    const array = generateTestArray();
    const newMap = new Map();
    array.forEach(({a, b}) => {
      newMap.set(a, b);
    });
    const foo = [...newMap.entries()];

  • for..of destructured

     
    const array = generateTestArray();
    const newMap = new Map();
    for(const {a, b} of array) {
        newMap.set(a, b);
    }
    const foo = [...newMap.entries()];

  • .forEach

     
    const array = generateTestArray();
    const newMap = new Map();
    array.forEach((x) => {
      const {a, b} = x;
      newMap.set(a, b);
    });
    const foo = [...newMap.entries()];

  • for..of

     
    const array = generateTestArray();
    const newMap = new Map();
    for(const x of array) {
        const {a, b} = x;
        newMap.set(a, b);
    }
    const foo = [...newMap.entries()];