git.r.bdr.sh - rbdr/dotfiles/blob

   1 // Based on:
   2 // http://norbertlindenberg.com/2012/05/ecmascript-supplementary-characters/
   3 // and:
   4 // https://github.com/mathiasbynens/String.fromCodePoint/blob/master
   5 // /fromcodepoint.js
   6
   7 'use strict';
   8
   9 var floor = Math.floor, fromCharCode = String.fromCharCode;
  10
  11 module.exports = function (codePoint/*, …codePoints*/) {
  12         var chars = [], l = arguments.length, i, c, result = '';
  13         for (i = 0; i < l; ++i) {
  14                 c = Number(arguments[i]);
  15                 if (!isFinite(c) || c < 0 || c > 0x10FFFF || floor(c) !== c) {
  16                         throw new RangeError("Invalid code point " + c);
  17                 }
  18
  19                 if (c < 0x10000) {
  20                         chars.push(c);
  21                 } else {
  22                         c -= 0x10000;
  23                         chars.push((c >> 10) + 0xD800, (c % 0x400) + 0xDC00);
  24                 }
  25                 if (i + 1 !== l && chars.length <= 0x4000) continue;
  26                 result += fromCharCode.apply(null, chars);
  27                 chars.length = 0;
  28         }
  29         return result;
  30 };