client/src/utils/alea.js

   1 // Random (enough) string for socket and game IDs
   2 export function getRandString() {
   3   return (
   4     Date.now().toString(36) +
   5     Math.random()
   6       .toString(36)
   7       .substr(2, 7)
   8   ).toUpperCase();
   9 }
  10
  11 export function randInt(min, max) {
  12   if (!max) {
  13     max = min;
  14     min = 0;
  15   }
  16   return Math.floor(Math.random() * (max - min)) + min;
  17 }
  18
  19 // Inspired by https://github.com/jashkenas/underscore
  20 export function sample(arr, n) {
  21   n = n || 1;
  22   let cpArr = arr.map(e => e);
  23   for (let index = 0; index < n; index++) {
  24     const rand = randInt(index, arr.length);
  25     [ cpArr[index], cpArr[rand] ] = [ cpArr[rand], cpArr[index] ];
  26   }
  27   return cpArr.slice(0, n);
  28 }
  29
  30 export function shuffle(arr) {
  31   return sample(arr, arr.length);
  32 }