JSFiddle - React, Tailwind, and code Playground

JavaScript

function Dictionary(values) {
    this.values = values || {};
        
    var forEachIn = function (object, action) {
      for (var property in object) {
        if (Object.prototype.hasOwnProperty.call(object, property))
          action(property, object[property]);
      }
    };
    
    Dictionary.prototype.containsKey = function(key) {
      return Object.prototype.hasOwnProperty.call(this.values, key) &&
        Object.prototype.propertyIsEnumerable.call(this.values, key);
    };
    
    Dictionary.prototype.forEach = function(action) {
      forEachIn(this.values, action);
    };

    Dictionary.prototype.lookup = function(key) {
      return this.values[key];
    };
    
    Dictionary.prototype.add = function(key, value) {
      this.values[key] = value;
    };
};

var numberDic = new Dictionary({One: 1,Two: 2, Three: 3});

//-- does key exist
console.log(numberDic.containsKey("One"));
console.log(numberDic.containsKey("One"));
console.log(numberDic.containsKey("Four"));

//-- loop through each item in the dic
numberDic.forEach(function(key, value) {
  console.log(key, "is", value);
});

//-- works with complex objects
//------------------------------------------
var complexObjectDic = new Dictionary({
    Microsoft: {
        Something: "Real Interesting",
        About: "Microsoft",
        Will: "Go",
        Here: ".",
        ProductPrices: {
            WindowsPhone: 55.88,
            Windows :{
                WinXp : 180.00,
                Win7 : 200.00,
                Win8 : 150.00
            }
        }
    },
    Apple: {
        Did: "you",
        Hear: "the",
        New: "iphone",
        Will: "be coming out soon",
    }});

//-- does key exist
console.log(complexObjectDic.containsKey("Microsoft"));
console.log(complexObjectDic.containsKey("Apple"));
console.log(complexObjectDic.containsKey("Facebook"));

//-- search the dic by...