JS 创建 Map

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;}