Lists of Unique Values - Using ES6 Sets in JavaScript

batmansPhoneBook

/*
** Pushing values to an array
*/
var heroCallList = [ ];

heroCallList.push("Robin");
heroCallList.push("Batgirl");
heroCallList.push("Nightwing");

console.log(heroCallList);
// => ["Robin", "Batgirl", "Nightwing"]
// Limitations: prone to duplication

/*
** Checking if value exsists before pushing values to an array
*/
var heroCallList = [ ];

function addToCallList(hero){
    var exists = false;
    
    for(var i = 0; i < heroCallList.length && !exists; i++){
        exists = heroCallList[i] === hero;
    }
    
    if (!exists){
    heroCallList.push(hero);
    }
         
}

addToCallList("Robin");
addToCallList("Batgirl");
addToCallList("Superman");
addToCallList("Batgirl");

console.log(heroCallList);
// = > ["Robin", "Batgirl", "Superman"]
// Limitations: With each add has to search the entire array, slow at scale

/*
** Storying values in an object
*/
var heroCallList = Object.create(null);

function addToCallList(hero){
    heroCallList[hero] = true;       
}

addToCallList("Robin");
addToCallList("Batgirl");
addToCallList("Superman");
addToCallList("Batgirl");

console.log(heroCallList);
// => Object {Robin: true, Batgirl: true, Superman: true};
// Limitations: unintuitive, can't reliably keep a list of anything but strings.

/*
** Storying values in ES6 set
*/
var heroCallList = new Set();

heroCallList.add("Robin");
heroCallList.add("Batgirl");
heroCallList.add("Superman");
heroCallList.add("Batgirl");

console.log(heroCallList);
// => Set [ "Robin", "Batgirl", "Superman" ]