const arr = [1, 2, 3, 4, 5, 6, 7, 8, 9];
const arr1 = [0, ...arr];
arr.unshift(0);
FAQ: FAQ
Source code: GitHub/MeasureThat.net
Report issues: MeasureThat.net/Issues
Based on: Benchmark.js
Facebook page: https://www.facebook.com/MeasureThat.Net
Python benchmarks support: Pyodide