bind返回的是一个函数，不会立即执行，需要手动触发

    1. // 实现bind方法
    2. Function.prototype.newBind = function (o) {
    3.   if (typeof this != 'function') {
    4.     throw new TypeError("error")
    5.   }
    6.   var that = this;
    7.   var arr = Array.prototype.slice.call(arguments, 1)
    8.   // 原型链 空函数桥接
    9.   var bridgeF = function () { }
    10.   newF = function () {
    11.     // console.log(this instanceof newF);
    12.     // console.log([...arguments]);
    13.     // that.apply(o, [...arr, ...arguments])
    14.     if (this instanceof bridgeF) {
    15.       that.apply(this, [...arr, ...arguments])
    16.     } else {
    17.       that.apply(o, [...arr, ...arguments])
    18.     }
    19.   }
    20.   bridgeF.prototype = that.prototype
    21.   newF.prototype = new bridgeF
    22.   return newF
    23.   // return function () {
    24.   //   console.log([...arguments]);
    25.   //   that.apply(o, [...arr, ...arguments])
    26.   // }
    27. }
    29. function person(a, b, c) {
    30.   console.log(this.name);
    31.   console.log("abc", a, b, c);
    32. }
    33. person.prototype.collection = "收藏"
    35. var obj = {
    36.   name: "xiao"
    37. }
    39. // person.newBind(obj, "test", "aa")("xixi")
    40. var bibi = person.newBind(obj, "test", "aa")
    41. var b = new bibi("xixi")
    42. console.log("b.collection", b.collection);
    44. /* 
    45. undefined
    46. newBind.js?9854:31 abc test aa xixi
    47. newBind.js?9854:42 b.collection 收藏
    48. */