JS mocking Map class implementation method

This article describes the Map class simulated by JS. Share it for your reference, as follows:

According to the properties of map in java, implement key----value saving

1. Use arrays to store data (using closures)

 function Map() { var struct = function (key, value) { this.key = key; this.value = value; } var put = function (key, value) { for (var i = 0; i < this.arr.length; i++) { if (this.arr[i].key === key) { this.arr[i].value = value; return; } } this.arr[this.arr.length] = new struct(key, value); } var get = function (key) { for (var i = 0; i < this.arr.length; i++) { if (this.arr[i].key === key) { return this.arr[i].value; } } return null; } var remove = function (key) { var v; for (var i = 0; i < this.arr.length; i++) { v = this.arr.pop(); if (v.key === key) { continue; } this.arr.unshift(v); } } var size = function () { return this.arr.length; } var isEmpty = function () { return this.arr.length <= 0; } this.arr = new Array(); this.get = get; this.put = put; this.remove = remove; this.size = size; this.isEmpty = isEmpty;}

2. Use JSON to store data (using prototype expansion method)

 function Map() { this.obj = {}; this.count = 0;}Map.prototype.put = function (key, value) { var oldValue = this.obj[key]; if (oldValue == undefined) { this.count++; } this.obj[key] = value;}Map.prototype.get = function (key) { return this.obj[key];}Map.prototype.remove = function (key) { var oldValue = this.obj[key]; if (oldValue != undefined) { this.count--; delete this.obj[key]; }}Map.prototype.size = function () { return this.count;}var map = new Map();map.put("key","map");map.put("key","map1");alert(map.get("key"));//map1map.remove("key");alert(map.get("key"));//undefined

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