Files
pics/lib/misc/randomrange.js
T
Thomas Lynch d8f2e8292f add eslint rules
no-template-curly-in-string (+find and fix minor bug in redirect)
curly
no-multiple-empty-lines
2022-05-03 04:48:43 +10:00

21 lines
500 B
JavaScript

'use strict';
const { promisify } = require('util')
, randomBytes = promisify(require('crypto').randomBytes);
//NOTE: should only be used for ints, floors your inputs
module.exports = async (min, max) => {
min = Math.floor(min);
max = Math.floor(max);
if (max <= min) {
return min;
}
const mod = max - min + 1;
const div = (((0xffffffff - (mod-1)) / mod) | 0) + 1;
let g;
do {
g = (await randomBytes(4)).readUInt32LE();
} while (g > div * mod - 1);
return ((g / div) | 0) + min;
};