let vs const - Let's discuss.

We all are familiar with the difference between const, let and var. If not, please read this.

Var, let and const- what's the difference?

Sarah Chima ・ Oct 25 '17 ・ 5 min read

#es6 #javascipt #newbie

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For those who are familiar, should know that in the modern-day JavaScript, YOU SHOULD NEVER USE var.

So now, what we are left with, is the let and const.

🔥 The two scenarios

People believe their ways of using them both. Strongly.

Here are the two types of people.

1) Those who use const for Constants (Like for const PI = 3.14)
2) Those who use const for everything that won't be let

📯 const for Constants

Some people believe that const should only be used for strictly constant values like the Action Type Reducer Strings, Math values and constants like PI, etc.

If you are that person, you are from team CONSTANT SPARINGLY.

📯 const for everything that won't be let

If you always use const, no matter what, and only use let when you change a variable, you are from team CONSTANT FOR ALL.

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There has been a lot of talk around it on Twitter due to this tweet by Dan Abramov.

Dan Abramov

@dan_abramov

TC39 members: const was a mistake.
Reddit: NO DAN YOU'RE WRONG YOU JUST DONT UNDERSTAND JAVASCRIPTS

12:53 PM - 21 Dec 2019

The tweet pretty much sums up that he is from the team CONSTANT SPARINGLY.

If you have been seeing WesBos' tutorials, he seems like he is from the team CONSTANT FOR ALL.

Dan has provided a beautiful explanation for why he thinks const shouldn't be used.

Also, this writeup here focuses on easily concluding this discussion. But still, what's your opinion on it?

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What do you prefer? Let's Discuss!

Comments

[Spyros Argalias]

constant for all. It's useful information to the developer about the future of the value (that it won't change). It follows that seeing let guarantees that the value will change because it is necessary.

The additional information can be helpful.

[Kumar Abhirup]

Agreed.

[Sam]

CONSTANT FOR ALL team member checking in.

[Kumar Abhirup]

Nice. I got a teammate. ⚡

[Pacharapol Withayasakpunt]

I believe, the best should be CONSTANT FOR ALL, and not only constant for all, but also IMMUTABILITY. That is, avoid mutation, whether instance or memory address.

[Kumar Abhirup]

I like that.

[Serhii]

Would you write about arrow functions?

[Kumar Abhirup]

Yes! What would you like to know from me?

[Serhii]

How to use them in general

[Kumar Abhirup]

DM me @kumar_abhirup on Twitter about this :)

[Apoorv Singal]

Well, variables delcared using const keyword are allocated on stack instead of the heap (unless you're using closures), making them way faster than the variables declared with let. So, constant for all.

[Kalaiarasan Pushpanathan]

I don't understand the hype of "arrow function" and "const" guy checks in. I understand the need but not the hype.

[Saurabh Daware 🌻]

const for all. Though I do agree to Dan's point that it can be confusing for beginner when you're dealing with objects.

[Kumar Abhirup]

🔥