for in / for of - Beau teaches JavaScript

For... in and for... of loops allow you to loop through property names and values in JavaScript.

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[lazarojoabe]

MAAN! You helped me so much! in the first 10s you just explained a stuff I spent a few hours to know and couldn't. You're amazing!

[climbers]

"for in" loops through innumerable properties, property "names" 0:05:
--1:58-2:16, object defined properties
--3:12, array numeric indexes & object defined properties

"for of" loops through iterable objects (i.e. array, map, set), property "values" 0:08:
--4:01-4:18, values in arrays

[ericzedd]

Just remember!
1. for (every prop in objects) { // do this } **objects - enumerable**
2. for (every item of array) { // do this } **arrays - iterable***

[khaledkharaz]

I was trying to understand this video i watched it many time but no point Then I decided to take break 30 min and come back to concentrate in last 10 video in this tuturiol and come back to this video just in one minute i find it very simple and clear new lesson today to take break after study couple of hour then come back will find everything easy, I love your video really very clear and important for everyone want to be perofessinal in JS Thank you bro

[AlmostFamous]

just remember by this:
for (let index in Arr) {
console.log(index + Arr[index] ); //gives fname beau
}
for (let item of Arr) {
console.log(item); //gives 3, 5, 7
}

[blackpurple]

This helped clear the difference between the 2 loops, thanks a lot

[studentcoder]

Wow, this is quite good! Though I think that instead of "x" the first variable name should've been "propertyName" -- just to make it more explicit and thus clear what's happening. And then maybe go over the code with "x" afterwards just to show that it really doesn't matter what that first variable is called.

Slightly more problematically, in the beginning, stating that "'for...in' will loop through property names and 'for...of' will loop through property values" can be confusing at first when compared to the later statement (beginning at around 2:15) that the former works on what is enumerable while the latter what is iterable. In that vein, finally, I also thought that the later contrast between the two was good but felt just a bit rushed somehow.

Still, overall a nice video for us beginners; thanks!

[KevinTempelx]

To those who maybe are still confused I'm going to help you out and I'm going to be very specific with each individual word because they all mean something very important.

( let x in person ) - Also known as - ( Let X go into the variable person )

1. (let) - tells x what to do
2. (x)- is what will be going into something
3. (In) - tells x to attach to the key properties inside the object
4. (person) - is the destination for x

[fatemeetsluck]

This makes a lot of sense. I see how I need to restructure the semantics of my knockoff JavaScript interpreter.

[davyjones]

Need to watch another video on "for..in" loops on the objects..

[julioSWAC]

Thank you! had to watch it few times but you taught it VERY well. Kudos!

[chestercopperpot]

your videos are helping me with the "WHY?" . thank you for these. :):)

[vijayrawat]

Thanks for clearing my confusion between them :)

[tomormiston]

one way of remembering : 'i' n --> ob 'j' ect [look visually similar]
so the other must be : off --> array

OR "I want to get to know you _in person_ " if you know that person is normally best as an object ?

[nabsteve]

Clearly and beautifully explained.
Thanks a lot!

[__jake.m]

Thank you for this! You've clearly described the difference between the two! 💪🏽

[mistermomo]

yeah i did not understand shoit. Mainly cuz i have more of a problem understanding syntax. It's so helpful when code is turned into english text, then I get it mad quickk

[jackm]

Why use For Of loop when you could just use a traditional loop to get the job done? I'm guessing it costs less memory, but with this explanation For Of and traditional loops seems identical. Cheers :)

[RurouniKenshinShinta]

ty for explanation clear and to the point.

[mdrohimsikder]

is it your actual typing speed? or editing?