Iterables return an iterator object. This object knows how to access items from a collection 1 at a time, while keeping track of its current position within the sequence.

 

let user = {  name: "sam", totalReplies: 17, isBlocked: false};user[Symbol.iterator] = function(){  let properties = Object.keys(this);  let count = 0;  let isDone = false;  let next = () => {    if(count >= properties.length){      isDone = true;    }    let value = this[properties[count++]];    return {done: isDone, value} ;  };  return { next };};