var appState = "1";
var regex = /^[0-3]$/;
var arr = ['1', '2', '3', '4'];
regex.test(appState);
arr.includes(appState);
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