set.js

function MySet() {  
    var collection = [];  
    this.has = function (element) {    
        return (collection.indexOf(element) !== -1);  
    }  
    this.values = function () {    
        return collection;  
    }  
    this.size = function () {    
        return collection.length;  
    }  
    this.add = function (element) {    
        if (!this.has(element)) {      
            collection.push(element);      
            return true;    
        }    
        return false;  
    }  
    this.remove = function (element) {    
        if (this.has(element)) {      
            index = collection.indexOf(element);      
            collection.splice(index, 1);      
            return true;    
        }    
        return false;  
    }  
    this.union = function (otherSet) {    
        var unionSet = new MySet();    
        var firstSet = this.values();    
        var secondSet = otherSet.values();    
        firstSet.forEach(function (e) {      
            unionSet.add(e);    
        });    
        secondSet.forEach(function (e) {      
            unionSet.add(e);    
        });    
        return unionSet;  }  
        this.intersection = function (otherSet) {    
            var intersectionSet = new MySet();    
            var firstSet = this.values();    
            firstSet.forEach(function (e) {      
                if (otherSet.has(e)) {        
                    intersectionSet.add(e);      
                }    
            });    
            return intersectionSet;  
        }  
        this.difference = function (otherSet) {    
            var differenceSet = new MySet();    
            var firstSet = this.values();    
            firstSet.forEach(function (e) {      
                if (!otherSet.has(e)) {        
                    differenceSet.add(e);      
                }    
            });    
            return differenceSet;  
        }  
        this.subset = function (otherSet) {    
            var firstSet = this.values();    
            return firstSet.every(function (value) {      
                return otherSet.has(value);    
            });  
        }
    }