| 'use strict'; |
| |
| var toPosInt = require('../number/to-pos-integer') |
| |
| , test = function (a, b) {}, desc, defineProperty |
| , generate, mixin; |
| |
| try { |
| Object.defineProperty(test, 'length', { configurable: true, writable: false, |
| enumerable: false, value: 1 }); |
| } catch (ignore) {} |
| |
| if (test.length === 1) { |
| // ES6 |
| desc = { configurable: true, writable: false, enumerable: false }; |
| defineProperty = Object.defineProperty; |
| module.exports = function (fn, length) { |
| length = toPosInt(length); |
| if (fn.length === length) return fn; |
| desc.value = length; |
| return defineProperty(fn, 'length', desc); |
| }; |
| } else { |
| mixin = require('../object/mixin'); |
| generate = (function () { |
| var cache = []; |
| return function (l) { |
| var args, i = 0; |
| if (cache[l]) return cache[l]; |
| args = []; |
| while (l--) args.push('a' + (++i).toString(36)); |
| return new Function('fn', 'return function (' + args.join(', ') + |
| ') { return fn.apply(this, arguments); };'); |
| }; |
| }()); |
| module.exports = function (src, length) { |
| var target; |
| length = toPosInt(length); |
| if (src.length === length) return src; |
| target = generate(length)(src); |
| try { mixin(target, src); } catch (ignore) {} |
| return target; |
| }; |
| } |