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JavaScript: Introduction to Scope (function scope, block scope)

Ming-Shiuan Tsai on November 27, 2018

What is Scope? Scope determines the visibility or accessibility of a variable or other resource in the area of your code. Glob...
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mdsameershaikh

Hi if you not have written {curly brackets} for explaining block scope, I could not understand it.

thanyou verymych for expaining in such easy language.

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N V S ABHISHEK

Nice article.

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Prof Great Wonder

Great article. Really helped me with understanding the block scope

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Tuan Nguyen

Great clear explain !!!

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Juan Alejandro Morais

Great article - thanks for sharing! :)

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TMsravan

Nice explanation

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Sashank Ramaraju

Very nice article on scopes !!!

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Siddh

If we are not able to reassign the value in the variable that is defined with the const
then why it is changing his value every time, when the loop gets executed

const array = [1,2,3,4] ;

for (let index = 0; index < array.length; index++) {
const element = array[index];
console.log(element);
}

answer is

1
2
3
4

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Dev Hamza

you are storing the array[index] in element
you are not re-declaring but you are updating the value of element

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M.Navid

Thank you @mingt .
I think there is a misinformation In "Lexical Scope" topic that you define it: "children scope have the access to the variables defined in the parent scope."
I think that definition is for "Scope Chain" and the "Lexical Scope" related to which type of referencing to parent in Scope Chain does JS (Lexical or Dynamic).

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Vikler Charles

Very helpful article! :)

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Gaurav Gupta

_Easy and Clear explanation: thanks for sharing this article. _

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Hafed Benchellali

Thank you I Finally understood !

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Mohamad-serhan

Fantastic, great job

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Tuyen Vd.

thank for your explantation

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Jan Anhalt

This was very helpful, thank you very much! :)

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João Antônio Feijó

Very cool explanation, straight to the point. I'm currently learning the scope subject on my bootcamp and you've made me understand it a lot better!

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Saroj Padhan

Nice explain of the scope

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Saroj Padhan

very nice explanation

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SHASHI JAISWAL

very very clear and vivid explanation. awesome

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GidoSkales

Well Orchestrated ....

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B77748

Thank you, it's very clear now.

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Mark Rubanza

nice explanation
salut

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Sanjar Afaq • Edited

This is really helpful, embed this picture as a summary if you want.

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Dev Hamza

thanks dude i used it in my notes

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KH

clear, helpful description of scope! Thanks!

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yusufnviiri

Thank you for such Great work

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Mahmoud Abdulmuty

Good Explanation .. thanks alot

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Umar Sanil

Good

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outman boko

Thank you so much for that explanation

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Md Pervez Hossain

Very much informative Article About Scope in JavaScript. Well Define.
Thank you

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Jyotirmoy Deb

is block scope and child scope same ?

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Oshie • Edited

I have not seen any simple explanation of function scope and block scope before. It is a worthwhile article to read, thanks

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Kibirige John

Thank you so much for the elaborative write-up

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Prince Djangmah

Awesome, simplified and tactical. Loved it.