JavaScript implements the Map structure in Java

Map in Java is a very practical collection. I am used to using Map in Java. I feel very uncomfortable when I switch to another language without Map. I have encountered situations where Map is needed when writing Flex AS code before, but AS actually There is a Dictionary dictionary class that can replace Map in Java. At the same time, Map can also be implemented using the attribute-value form of an object. Here, the Map implementation of JS uses the attribute-value of the object. The implementation is very simple, this is just to allow Java programmers to easily write JS code.

//construction
function Map() {
        this.obj = new Object();
};
 
//add a key-value
Map.prototype.put = function(key, value) {
        this.obj[key] = value;
};
 
//get a value by a key,if don't exist,return undefined
Map.prototype.get = function(key) {
        return this.obj[key];
};
 
//remove a value by a key
Map.prototype.remove = function(key) {
        if(this.get(key)==undefined) {
                return;
        }
        delete this.obj[key];
};
 
//clear the map
Map.prototype.clear = function() {
        this.obj = new Object();
};
 
//get the size
Map.prototype.size = function() {
        var ary = this.keys();
        return ary.length;
};
 
//get all keys
Map.prototype.keys = function() {
        var ary = new Array();
        for(var temp in this.obj) {
                ary.push(temp);
        }
        return ary;
};
 
//get all values
Map.prototype.values = function() {
        var ary = new Array();
        for(var temp in this.obj) {
                ary.push(this.obj[temp]);
        }
        return ary;
};