set

by John Kiran

HTML

<p id="demo">

</p>

JavaScript

let para=document.getElementById("demo");

let set = new Set();

let john = { name: "John" };
let pete = { name: "Pete" };
let mary = { name: "Mary" };

// visits, some users come multiple times
set.add(john);
set.add(pete);
set.add(mary);
set.add(john);
set.add(mary);
set.add("ID",3);

// set keeps only unique values
para.innerHTML+=(set.size)+"<br>";

for (let user of set) {
  para.innerHTML+=(user.name)+"<br>";
}

alert(Array.from(set));