javascript字典数据结构常用功能实现

function Dictionary(){
var items = {};

this.has = function (key) {
return key in items;
};

this.set = function(key, value){
items[key] = value;
};

this.remove = function(key){
if (this.has(key)){
delete items[key];
return true;
}
return false;
};

this.get = function(key){
return this.has(key) ? items[key] : undefined;
};

this.values = function(){
var values = [];
for(var k in items){
if (this.has(k)) {
values.push(items[k]);
}
}
return values;
};

this.clear = function(){
items = {};
};

this.size = function(){
var count = 0;
for (var prop in items){
if(items.hasOwnProperty(prop)){
++count;
}
}
return count;
};

this.getItems = function(){
return items;
};
}

var dictionary = new Dictionary();
dictionary.set('Gandalf', 'gandalf@email.com');
dictionary.set('John', 'johnsnow@email.com');
dictionary.set('Tyrion', 'tyrion@email.com');

console.log(dictionary.has('Gandalf'));
console.log(dictionary.size());

//console.log(dictionary.keys());
console.log(dictionary.values());
console.log(dictionary.get('Tyrion'));

dictionary.remove('John');

console.log(dictionary.values());
console.log(dictionary.get('Tyrion'));