[d565449] | 1 | 'use strict';
|
---|
| 2 |
|
---|
| 3 | /* eslint no-invalid-this: 1 */
|
---|
| 4 |
|
---|
| 5 | var ERROR_MESSAGE = 'Function.prototype.bind called on incompatible ';
|
---|
| 6 | var toStr = Object.prototype.toString;
|
---|
| 7 | var max = Math.max;
|
---|
| 8 | var funcType = '[object Function]';
|
---|
| 9 |
|
---|
| 10 | var concatty = function concatty(a, b) {
|
---|
| 11 | var arr = [];
|
---|
| 12 |
|
---|
| 13 | for (var i = 0; i < a.length; i += 1) {
|
---|
| 14 | arr[i] = a[i];
|
---|
| 15 | }
|
---|
| 16 | for (var j = 0; j < b.length; j += 1) {
|
---|
| 17 | arr[j + a.length] = b[j];
|
---|
| 18 | }
|
---|
| 19 |
|
---|
| 20 | return arr;
|
---|
| 21 | };
|
---|
| 22 |
|
---|
| 23 | var slicy = function slicy(arrLike, offset) {
|
---|
| 24 | var arr = [];
|
---|
| 25 | for (var i = offset || 0, j = 0; i < arrLike.length; i += 1, j += 1) {
|
---|
| 26 | arr[j] = arrLike[i];
|
---|
| 27 | }
|
---|
| 28 | return arr;
|
---|
| 29 | };
|
---|
| 30 |
|
---|
| 31 | var joiny = function (arr, joiner) {
|
---|
| 32 | var str = '';
|
---|
| 33 | for (var i = 0; i < arr.length; i += 1) {
|
---|
| 34 | str += arr[i];
|
---|
| 35 | if (i + 1 < arr.length) {
|
---|
| 36 | str += joiner;
|
---|
| 37 | }
|
---|
| 38 | }
|
---|
| 39 | return str;
|
---|
| 40 | };
|
---|
| 41 |
|
---|
| 42 | module.exports = function bind(that) {
|
---|
| 43 | var target = this;
|
---|
| 44 | if (typeof target !== 'function' || toStr.apply(target) !== funcType) {
|
---|
| 45 | throw new TypeError(ERROR_MESSAGE + target);
|
---|
| 46 | }
|
---|
| 47 | var args = slicy(arguments, 1);
|
---|
| 48 |
|
---|
| 49 | var bound;
|
---|
| 50 | var binder = function () {
|
---|
| 51 | if (this instanceof bound) {
|
---|
| 52 | var result = target.apply(
|
---|
| 53 | this,
|
---|
| 54 | concatty(args, arguments)
|
---|
| 55 | );
|
---|
| 56 | if (Object(result) === result) {
|
---|
| 57 | return result;
|
---|
| 58 | }
|
---|
| 59 | return this;
|
---|
| 60 | }
|
---|
| 61 | return target.apply(
|
---|
| 62 | that,
|
---|
| 63 | concatty(args, arguments)
|
---|
| 64 | );
|
---|
| 65 |
|
---|
| 66 | };
|
---|
| 67 |
|
---|
| 68 | var boundLength = max(0, target.length - args.length);
|
---|
| 69 | var boundArgs = [];
|
---|
| 70 | for (var i = 0; i < boundLength; i++) {
|
---|
| 71 | boundArgs[i] = '$' + i;
|
---|
| 72 | }
|
---|
| 73 |
|
---|
| 74 | bound = Function('binder', 'return function (' + joiny(boundArgs, ',') + '){ return binder.apply(this,arguments); }')(binder);
|
---|
| 75 |
|
---|
| 76 | if (target.prototype) {
|
---|
| 77 | var Empty = function Empty() {};
|
---|
| 78 | Empty.prototype = target.prototype;
|
---|
| 79 | bound.prototype = new Empty();
|
---|
| 80 | Empty.prototype = null;
|
---|
| 81 | }
|
---|
| 82 |
|
---|
| 83 | return bound;
|
---|
| 84 | };
|
---|