Javascript for in and for of

Day 4: for in and for of loops

In short, Iterates over statements which are true.

 

The differences between for of and for in are illustrated below. However, I still can’t wrap my head around it.

Object.prototype.objCustom = function() {};
Array.prototype.arrCustom = function() {};
let iterable = [3, 5, 7];
iterable.foo = 'hello';
for (let i in iterable) {
console.log(i); // logs 0, 1, 2, "foo", "arrCustom", "objCustom"
}
for (let i of iterable) {
console.log(i); // logs 3, 5, 7
}

Javascript Loop

Day Two – Loops

Took a look at the for and for / in loops and how they’re used in variables and objects to pull information.

var warGoodForObject = {
"what": "nothing",
"who": "no one"
};
for( var name in warGoodForObject ) {
console.log ( name + ": " + warGoodForObject[name] );
}

Results in console:
what: nothing
who: no one