Array和 Array.prototype

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Array和 Array.prototype 的定义

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Array 对象是用于构造数组的全局对象，数组是类似于列表的高阶对象
Array.prototype 属性表示 Array 构造函数的原型，并允许您向所有Array对象添加新的属性和方法。

获取相应的属性名称

 Object.getOwnPropertyNames(Array)
//[ "length", "name", "prototype", "isArray", "from", "of" ]

Object.getOwnPropertyNames(Array.prototype)
//[ "length", "constructor", "concat", "copyWithin", "fill", "find", "findIndex", "pop", "push",
 "reverse", "shift", "unshift", "slice", "sort", "splice", "includes", "indexOf", "keys", "entries",
 "forEach", "filter", "map", "every", "some", "reduce", "reduceRight", "toString", "toLocaleString", 
"join", "lastIndexOf", "values", "flat", "flatMap" ]

• Array是一个 function 对象，是JS的内置对象。js中所有的数组方法均来自于Array.prototype，和其他构造函数一样，你可以通过扩展 Array 的 prototype 属性上的方法来给所有数组实例增加方法

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Array.prototype 的用法

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1. 给 Array 对象添加新的方法

    Array.prototype.duplicator = function() {
    let s = this.concat(this) 
      return s
    }
    let t = [1,2,3,4,5].duplicator()
    console.log(t) // [1, 2, 3, 4, 5, 1, 2, 3, 4, 5]
   

2. JS合并两个数组的方法

    var array = ["football", "basketball"];
    var array2 = ["volleyball", "golfball"];
    var i = Array.prototype.push.apply(array,array2);
    console.log(array); // ["football", "basketball", "volleyball", "golfball"]
    console.log(i); // 4