Javacript中自定义的map.js  的方法

js中没有map这个类，只能自己写一个。以下map.js和map-util.js都是自定义的map，任选其一就可以。你可以用它来像java里new Map()和put()、remove()、get()等方法。

map.js:

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;
}   

map-util.js:

function Map() {
  this.elements = new Array();
  var i;
  //获取MAP元素个数
  this.size = function() {
    return this.elements.length;
  };
  //判断MAP是否为空
  this.isEmpty = function() {
    return (this.elements.length < 1);
  };
  //删除MAP所有元素
  this.clear = function() {
    this.elements = new Array();
  };
  //向MAP中增加元素（key, value)
  this.put = function(_key, _value) {
    this.elements.push( {
      key : _key,
      value : _value
    });
  };
  this.putFirst = function(_key, _value){
    var tempList = this.elements;
    this.elements = new Array();
    this.elements.push( {
      key : _key,
      value : _value
    });
    for(var i=0;i<tempList.length;i++){
      this.elements.push(
        tempList[i]
      );
    }
  }
  //删除指定KEY的元素，成功返回True，失败返回False
  this.remove = function(_key) {
    var bln = false;
    try {
      for (i = 0; i < this.elements.length; i++) {
        if (this.elements[i].key == _key) {
          this.elements.splice(i, 1);
          return true;
        }
      }
    } catch (e) {
      bln = false;
    }
    return bln;
  };
  //获取指定KEY的元素值VALUE，失败返回NULL
  this.get = function(_key) {
    try {
      for (i = 0; i < this.elements.length; i++) {
        if (this.elements[i].key == _key) {
          return this.elements[i].value;
        }
      }
    } catch (e) {
      return null;
    }
  };
  //获取指定索引的元素（使用element.key，element.value获取KEY和VALUE），失败返回NULL
  this.element = function(_index) {
    if (_index < 0 || _index >= this.elements.length) {
      return null;
    }
    return this.elements[_index];
  };
  //判断MAP中是否含有指定KEY的元素
  this.containsKey = function(_key) {
    var bln = false;
    try {
      for (i = 0; i < this.elements.length; i++) {
        if (this.elements[i].key == _key) {
          bln = true;
        }
      }
    } catch (e) {
      bln = false;
    }
    return bln;
  };
  //判断MAP中是否含有指定VALUE的元素
  this.containsValue = function(_value) {
    var bln = false;
    try {
      for (i = 0; i < this.elements.length; i++) {
        if (this.elements[i].value == _value) {
          bln = true;
        }
      }
    } catch (e) {
      bln = false;
    }
    return bln;
  };
  //获取MAP中所有VALUE的数组（ARRAY）
  this.values = function() {
    var arr = new Array();
    for (i = 0; i < this.elements.length; i++) {
      arr.push(this.elements[i].value);
    }
    return arr;
  };
  //获取MAP中所有KEY的数组（ARRAY）
  this.keys = function() {
    var arr = new Array();
    for (i = 0; i < this.elements.length; i++) {
      arr.push(this.elements[i].key);
    }
    return arr;
  };
} 

总结

以上所述是小编给大家介绍的 Javacript中自定义的map.js  的方法，希望对大家有所帮助，如果大家有任何疑问欢迎给我留言，小编会及时回复大家的！