JS generate random boolean
You can compare Math.random() to 0.5 directly, as the range of Math.random() is [0, 1) (this means 'in the range 0 to 1 including 0, but not 1'). You can divide the range into [0, 0.5) and [0.5, 1).
var random_boolean = Math.random() < 0.5;// Exampleconsole.log(Math.random() < 0.1); //10% probability of getting trueconsole.log(Math.random() < 0.4); //40% probability of getting trueconsole.log(Math.random() < 0.5); //50% probability of getting trueconsole.log(Math.random() < 0.8); //80% probability of getting trueconsole.log(Math.random() < 0.9); //90% probability of getting true
For a more cryptographically secure value, you can use crypto.getRandomValues in modern browsers.
Sample:
var randomBool = (function() { var a = new Uint8Array(1); return function() { crypto.getRandomValues(a); return a[0] > 127; };})();var trues = 0;var falses = 0;for (var i = 0; i < 255; i++) { if (randomBool()) { trues++; } else { falses++; }}document.body.innerText = 'true: ' + trues + ', false: ' + falses;Note that the crypto object is a DOM API, so it's not available in Node, but there is a similar API for Node.