Paul Irish

Making the www great

Random Hex Color Code Generator in JavaScript

For fun I asked a few friends for ideas on a random color generator in a single line of javascript. You know, these guys: #0afec0, #c9f2d0, #9b923e.

Here’s what we came up in about two minutes (in chronological order)…

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'#' + (function co(lor){   return (lor +=
  [0,1,2,3,4,5,6,7,8,9,'a','b','c','d','e','f'][Math.floor(Math.random()*16)])
  && (lor.length == 6) ?  lor : co(lor); })('');

Similar recursive technique, but using a string instead of an array and aliasing the Math object:

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(function(m,s,c){return (c ? arguments.callee(m,s,c-1) : '#') +
  s[m.floor(m.random() * s.length)]})(Math,'0123456789ABCDEF',5)

Using a named function expression instead of arguments.callee.

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'#'+(function lol(m,s,c){return s[m.floor(m.random() * s.length)] +
  (c && lol(m,s,c-1));})(Math,'0123456789ABCDEF',4)

If we assume JavaScript 1.6, then we could just use Array.map():

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'#'+'0123456789abcdef'.split('').map(function(v,i,a){
  return i>5 ? null : a[Math.floor(Math.random()*16)] }).join('');

But then, the magic of Math struck (16777215 == ffffff in decimal):

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'#'+Math.floor(Math.random()*16777215).toString(16);
Thx to ben alman, nlogax, and temp01 for their smarts.

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