Javascript iterators

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Standard loops:

//standrd for loop
for(let i=0; i<10; i++) { }

//for in: loop over properties of an object
//loop each property of obj
for(let prop in obj) { }

//for of: loop over iterable objects such as elements in an array
let a = [1,2,3];
//loops over each element in the array
for (let element of a) { }

// .forEach()
[1, 2, 3].forEach( i => { doSomethingWith } );

Iterators:
- anything that implements Iterator protocol by implementing next() that returns a value and a done property

//Get an iterator from Iterable objects, like Map and Set
let map = new Map();
let mapIter = map[Symbol.Iterator]();
let i = mapIter.next();
console.log(i.value + " : " + i.done);