DEV Community

10 JavaScript concepts every Node developer must master

USMAN AWAN on October 05, 2024

Node.js has quickly become a standard for building web apps and systems software, thanks to its ability to leverage JavaScript on the back end. Pop...

Read full post

Serhiy • Oct 7

but why do you use var?

WORMSS • Oct 8

I am guessing someone who likes the nasty habit of hoisting. I would put money on them not being fans of Typescript.
I don't mind function hoisting, but I don't know of anyone who likes variable hoisting.
Though, I find people who use let for absolutely everything to be strange also.. I use const for everything unless I absolutely HAVE to use a reassigning variable, which is maybe only 1% of the time at most.

Jonathan DS • Oct 9

Is it hoisting or just global scope?

WORMSS • Oct 9

Hoisting. Because if you are inside another scope (closure for example) it's no longer globally available.

minoblue • Oct 14 • Edited

One usecase is when we want to access variable outside the block within the function.

function example() {
  if (true) {
    var x = 10;  // 'var' is function-scoped, not block-scoped
    let y = 20; // 'let' is block-scoped
  }
  console.log(x); // Accessing 'x' outside the 'if' block
  console.log(y); // ReferenceError: y is not defined
}

Adnan Babakan (he/him) • Oct 6

Good points to remember in JS. I really enjoyed reading it.

USMAN AWAN • Oct 6

Thank you very much 😊

shield8994 • Oct 7

Your article is well written. I am the operator of servbay. Can you promote our products? Our official website is servbay.com. If you are willing, we can give you some channel discounts.

USMAN AWAN • Oct 7

I would be an honour 😊😋

shield8994 • Oct 8

How can I contact you? Email?

Abid • Oct 8

Hi, is it not for windows users? I can not find any link for windows on your website.

Brad • Oct 7

I gotta point it out.

It seems like the code examples have inconsistent indentation? 🤔

Shahadat Hossain • Oct 8

Javascript and Node becoming more popular among developers. it is not bind only for web applications; we are building more complex applications like IOT, machine learning, chatbots, ect.
it is a really game changer for developer.

Yurii Timofeev • Oct 8

Good advice... for 2014

Friday candour • Oct 7

It's for beginners

WORMSS • Oct 8

Technically it's for 'everyone'.
Beginners will be learning about it, and for advanced people, it's a checkbox exercise to say "yep, I know these concepts".. It's not like, once you are past the beginners stage, you can forget these concepts..
It's always good to remember that async/await is sugar for Promises/then, and class declarations is sugar for prototype. It's good to remember that these are what is happening under the hood. Even if you don't touch these old ways anymore.

Marc • Oct 7

advanced beginners ;-)

Tom Pereira • Oct 8

Shouldn't:

the CommonJS include syntax and the ES6 require syntax.

...read:

the CommonJS require syntax and the ES6 include syntax.

William Bernfield • Oct 10

Hello everyone, id live to get some help, Also how do you all feel about Quantum capabilities ? Early access

almogzur • Oct 7

Vary nice

Robert Snedeker • Oct 7

Great article! I recently discovered the # private property/method thing in JS. But now that I use TS it's not something I use, still cool to see that JS is getting more OOP features though.

ArsalanNury • Oct 8 • Edited

Thanks, I haven't seen anyone use IIFE in real programs. I think just Webpack and Babel are use it :-))))

I find rest operators the most useful section in this article my friend

José Pablo Ramírez Vargas • Oct 11

UMD modules are basically IIFE's. AngularJS had heavy use of IIFE's. Finally, CommonJS can see them used to encapsulate await syntax.

Alexander Borshak • Oct 9

Did you ever use jQuery? Aside of it, IIFE used often when you have to perform some actions during init stage of ESM module.

Softwaredevelopmentinsights • Oct 10

Great insights on JS. It is very informative.

The Eagle 🦅 • Oct 9

I've had fun reading this article, thanks bro!

Rafa Rios • Oct 9

Nice article to bear in mind. Thanks for the clear examples

sachin kotian • Oct 9

nice article but try pasting code instead of screenshots

David Sabalete • Oct 11

Thank you!

retrop5 • Oct 10

The first I learnt / heard of curry functions and I love it, I am gonna keep using it extensively moving forward

killer space • Nov 8

broo ,really this is way advanced for a beginner in js

USMAN AWAN • Nov 8

😊

Axorax • Oct 8

cool article :D

Vivek Garg • Oct 8

Love these insights keep sharing such valuable thoughts.

RamR • Oct 8

nice post

Adesh Tamrakar • Oct 7

This is going to be my everytime go-to revision list. Thanks.

USMAN AWAN • Oct 7

Glad to hear it 😊

Yair Nevet • Oct 8

Great post! However, it's a shame that the code examples are presented as images instead of regular text, as it makes it harder for readers to copy and test the code themselves.