Spaces:
Running
Running
; | |
/* eslint no-invalid-this: 1 */ | |
var ERROR_MESSAGE = 'Function.prototype.bind called on incompatible '; | |
var slice = Array.prototype.slice; | |
var toStr = Object.prototype.toString; | |
var funcType = '[object Function]'; | |
module.exports = function bind(that) { | |
var target = this; | |
if (typeof target !== 'function' || toStr.call(target) !== funcType) { | |
throw new TypeError(ERROR_MESSAGE + target); | |
} | |
var args = slice.call(arguments, 1); | |
var bound; | |
var binder = function () { | |
if (this instanceof bound) { | |
var result = target.apply( | |
this, | |
args.concat(slice.call(arguments)) | |
); | |
if (Object(result) === result) { | |
return result; | |
} | |
return this; | |
} else { | |
return target.apply( | |
that, | |
args.concat(slice.call(arguments)) | |
); | |
} | |
}; | |
var boundLength = Math.max(0, target.length - args.length); | |
var boundArgs = []; | |
for (var i = 0; i < boundLength; i++) { | |
boundArgs.push('$' + i); | |
} | |
bound = Function('binder', 'return function (' + boundArgs.join(',') + '){ return binder.apply(this,arguments); }')(binder); | |
if (target.prototype) { | |
var Empty = function Empty() {}; | |
Empty.prototype = target.prototype; | |
bound.prototype = new Empty(); | |
Empty.prototype = null; | |
} | |
return bound; | |
}; | |