Compare different approaches to string replace all in JS for performance

compare-string-replace.ts

/**
 * As of 2024-12-28, Mac M1 Max
 *
 * replace took 592ms
 * replaceAll took 641ms
 * replace regex took 485ms
 * replace NEW regex took 902ms
 * replaceAll regex took 691ms
 * replaceAll NEW regex took 1105ms
 */
function main() {
  const iterations = 10_000_000;
  const original = "1234567890abcdefghijklmnopqrstuvwxyz-+=;'";

  let start = Date.now();
  for (let i = 0; i < iterations; i++) {
    // Not really fair as this only replaces the first instance of the string
    original.replace("-", "");
  }
  console.log(`replace took ${Date.now() - start}ms`);

  start = Date.now();
  for (let i = 0; i < iterations; i++) {
    original.replaceAll("-", "");
  }
  console.log(`replaceAll took ${Date.now() - start}ms`);

  start = Date.now();
  for (let i = 0; i < iterations; i++) {
    original.replace(/-/g, "");
  }
  console.log(`replace regex took ${Date.now() - start}ms`);

  start = Date.now();
  for (let i = 0; i < iterations; i++) {
    const reg = new RegExp("-", "g");
    original.replace(reg, "");
  }
  console.log(`replace NEW regex took ${Date.now() - start}ms`);

  start = Date.now();
  for (let i = 0; i < iterations; i++) {
    original.replaceAll(/-/g, "");
  }
  console.log(`replaceAll regex took ${Date.now() - start}ms`);

  start = Date.now();
  for (let i = 0; i < iterations; i++) {
    const reg = new RegExp("-", "g");
    original.replaceAll(reg, "");
  }
  console.log(`replaceAll NEW regex took ${Date.now() - start}ms`);
}

main();