17: Let and Const Variables | JavaScript Block Scope and Function Scope | JavaScript Tutorial

In this JavaScript tutorial you will learn about the new variables called "let" and "const" which will replace the usage of "var". However in order to understand these new variables we also need to cover something called "function scope" and "block scope" which is also tied together with the previous lesson.

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[vanessawang]

Very good quality videos. Out of all the JavaScript YouTube tutorials I've watched, yours are the best! Thank you for doing such an awesome job explaining every concept.

[GelsYT]

Don't say your tutorials are bad man. You're good :)

[chalupabatman]

as a complete novice, these videos are outstanding, your time is much appreciated!!

[SethBocknek]

awesome video.
your clarity of voice and thought is fantastic—awesome teacher!

[angelosaballegue]

you kept saying your videos are bad yet it gives me clearer understanding after I finished all these lessons in freecodecamp

[nishamakhija]

you are "THE BEST" for language learning

[hannahsLifeandLiving]

you are not like other youtuber that creates tutorials just for the sake of money. while watching your videos, it really shows that you want to help other people to learn to code. thank you so much for that. you are a great teacher !

[dioncadiz]

Studying JS right now understanding things that happen "under the hood" and this is the best video so far regarding the behavior of var inside functions as compared to ifs/while etc.

[munch]

Dude, your videos are clear to a full 100%. Sometimes, it might be like too much info in a short amount of time (as it normally is with YT tutorials) so I just take like a minute-breather, revise in my head what you said, think at it in logical sense and then I return to watching the rest of your video. You cleared my basics to the level of how even HTML/ CSS/ Java Script for Dummies books couldn't. You make the concepts clearer, and infact make me look at it logically so that it infact appears easier to understand and learn. Thanks you

[hishamalhadi]

I love Elon Musk's younger brother teaching me JavaScript! :D

[arbimarkari]

You are almost the best tutorial maker i've ever seen.

[geraldfoushee]

Daniel, you are a really good teacher. I understood all of that perfectly. And I am glad you are currently doing your JavaScript series because most others only have a series from 2015 or older. I had heard this let and const mentioned here and there but this is the first time I have heard it explained. Thanks

[franklopez]

To summarize this video
-Function scope is whenever you declare a variable in a function, the variable is visible only within the function.
-Block scope is the area within if, switch conditions or for and while loops. Whenever you see {curly brackets}, it is a block.
-The difference between let and var is scoping rules.
-const behave like let variables but can not be reassigned and the variable names for const are all uppercase.

[braker]

The tutorials are great, man. Sometimes I have to rewind a little bit and re-watch certain parts, but hey, that's really similar to asking the teacher a question when in actual class.

[Kickflipr]

I'm a little bit of a dipshit when it comes to comprehending things I'm new at or just trying to understand, and most of the time I need to be taught things like I'm in kindergarten. You put everything in perfect context that makes it easy on my brain and I'm really hyped that I found your channel. Keep this up!! You're just what I needed.

[otistories]

You are the best person that have explained this

[Dentiddo]

thank you clearing up why to use const and let and not var. I had been struggling with the concept and you helped with providing more clarity on the 3 variable types. Much appreciated.

[SamVerrall]

I enjoy and learn alot from your videos. Very clear and confident teacher. Good job!

[shyamgopi]

Goodness... it’s crystal clear now. Thanks mate

[roysmith]

I understood everything just fine. Your videos are great. I finished your HTML/CSS course, and now I'm watching your Javascript course.