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

   1 'use strict';
   2
   3 var toPosInt = require('../number/to-pos-integer')
   4
   5   , test = function (a, b) {}, desc, defineProperty
   6   , generate, mixin;
   7
   8 try {
   9         Object.defineProperty(test, 'length', { configurable: true, writable: false,
  10                 enumerable: false, value: 1 });
  11 } catch (ignore) {}
  12
  13 if (test.length === 1) {
  14         // ES6
  15         desc = { configurable: true, writable: false, enumerable: false };
  16         defineProperty = Object.defineProperty;
  17         module.exports = function (fn, length) {
  18                 length = toPosInt(length);
  19                 if (fn.length === length) return fn;
  20                 desc.value = length;
  21                 return defineProperty(fn, 'length', desc);
  22         };
  23 } else {
  24         mixin = require('../object/mixin');
  25         generate = (function () {
  26                 var cache = [];
  27                 return function (l) {
  28                         var args, i = 0;
  29                         if (cache[l]) return cache[l];
  30                         args = [];
  31                         while (l--) args.push('a' + (++i).toString(36));
  32                         return new Function('fn', 'return function (' + args.join(', ') +
  33                                 ') { return fn.apply(this, arguments); };');
  34                 };
  35         }());
  36         module.exports = function (src, length) {
  37                 var target;
  38                 length = toPosInt(length);
  39                 if (src.length === length) return src;
  40                 target = generate(length)(src);
  41                 try { mixin(target, src); } catch (ignore) {}
  42                 return target;
  43         };
  44 }