Run results for: Push vs Spread vs Double loop Ultimate

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser: Chrome 103

Operating system: Windows

Device Platform: Desktop

Date tested: 2 years ago

Script Preparation code:

  var iterations = 50000;

  var a = [];

  for (let i = 0; i < iterations; i++) {
    a.push(Math.round(Math.random() * iterations));
  }

Tests:

Reduce and push
const result = a.reduce((acc, item, index) => { if(item % 2 === 0) { acc.push({ [index]: item }); } return acc}, []); console.log("Reduce and push", result.length);
Reduce and spread
const result = a.reduce((acc, item, index) => (item % 2 === 0 ? [...acc, { [index]: item }] : acc), []); console.log("Reduce and spread", result.length);
Filter and map
const result = a.filter(item => item % 2 === 0).map((oddItem, index) => ({ [index]: oddItem })); console.log("Filter and map", result.length);