Immediately Invoked Function Expression - Beau teaches JavaScript

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An Immediately Invoked Function Expression (IIFE) is a JavaScript function that runs as soon as it is defined.
💻 Code: codepen.io/beaucarnes/pen/KWOr...
🔗 Resource: en.wikipedia.org/wiki/Immedia...
🐦 Beau Carnes on Twitter: / carnesbeau
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Опубликовано:

9 апр 2017

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Комментарии : 64

@joellim7010 6 лет назад

wow. normally when i watch JS videos on youtube, i don't understand what is happening at all. but i actually understand this video. this is amazing.

@georgefox2767 3 года назад

This was the video I needed to finally understand IIFEs, thanks!

@pippinbloom 2 года назад

This was very hepful. Thank you so much for taking the time to make this!

@victorfeight9644 2 года назад

Very clear, and especially appreciate the new ES6 block scope syntax comparison.

@ElrondMcBong86 2 года назад

Awesome. short, clear, to the point! thanks! usefull extra-information!: I had the first situation, where i got errors, caused by not using semicolons. so after that self-calling function you HAVE to put the semicolon, since () followed by ( is valid syntax, and thatfore no semicolon is added/interpretet internally.

@kuilyniroshan5679 4 года назад

wow that was really clear, finally understood it!! thank you!!

@thematrixcam 3 года назад

Thanks for actually helping me understand this

@mandihaase2744 3 года назад

I finally think I understand IIFEs. Thank you!

@jerry861200 2 года назад

Great explanation. Thank you so much.

@edosaogbevoen7985 Год назад

Straight to the point. Thanks sir

@meeeeeraj 9 месяцев назад

best explanation this used to be super confusing for me thank you

@osamagamal495 5 лет назад

what a great explanation!

@tehrackoon2021 4 года назад

This video explained the value of let and const to me in es6

@harrazmasri2805 Год назад

my senior was using this and led me here. thanks

@ozzyfromspace 2 года назад

lol I've done this for years, didn't know it had a name 😂 Nice video, Beau!

@tung01vuongtri33 2 года назад

You guys are the best, thank you for creating freecodecamp. And thanks Beau for making this video.

@learnwithyan Год назад

Дякую вам, дуже доступно

@jessietorres1387 4 года назад

Great explanation! :-)

@oybektoshmatov9508 5 лет назад

well explained!

@hashtagtrends9886 3 года назад

Thank you!

@vanthuanluong9398 4 года назад

very nice. thanks

@PV_98 Год назад

Brilliant!

@WiLDeveD Год назад

Use Your Code For Good... Thanks Beau.

@thebmusproject 4 года назад

Thanks!

@BUCKTHEWORD14 7 лет назад

Always wondered what this was for..... Could you make a video on 'use strict';? Thanks

@freecodecamp 7 лет назад

Ta da! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-uqUYNqZx0qY.html

@BUCKTHEWORD14 7 лет назад

Thanks!

@mega_0319 7 лет назад

Dude your videos are awesome. Question for you - with ES6, do we need to use IIFE much anymore if at all?

@CameronChardukian 5 лет назад

Does anyone have an answer to this?

@jaydeest 4 года назад

@Shoaib Bhimani dont modules use IIFE's though?

@bvsanchez6161 2 года назад

For once Beu explains something well in javascript! yaaaay

@dzienisz 9 месяцев назад

What do you think is a real case use of IIFE in a commercial app?

@harmanpreetbhatti4354 5 лет назад

I think all the variables defined using 'var' are function scope in ES5 not global scope as you said @3:17

@kumarmanish9046 2 года назад

I have the same confusion. var a inside function is STILL not polluting the var a that is outside. Why do we need to INVOKE it immediately?

@moshemo613 3 года назад

why do the first enclosing parenthesis make the function an expression?

@randolphperkins6584 4 года назад

Hello. Great video, and very useful. But two things: it was hard to follow because it seemed to be fast forwarded, and new concepts were being introduced in rapid succession, making it hard to keep up. The second thing is it was difficult to follow when the console log was halfway cut off of the screen and you kept jumping back and forth between the console and the environment. And yet, a whole wealth of black space exists in the middle of the screen. If you would just move the screen margins over so the viewer can see the whole environment and the whole of the console, that would be very helpful for comprehension.

@jonahprinceton8132 2 года назад

i realize I'm quite off topic but do anyone know a good website to stream new tv shows online ?

@blazetaylor367 2 года назад

@Jonah Princeton flixportal xD

@jonahprinceton8132 2 года назад

@Blaze Taylor thanks, signed up and it seems like a nice service :) I appreciate it!

@blazetaylor367 2 года назад

@Jonah Princeton happy to help :D

@acethomas5774 4 года назад

Does anyone know how to write JavaScript functions for games (street wars)

@187hooman 6 лет назад

Is the video being slightly fast-forwarded while he types?

@BeauCarnes 6 лет назад

Yup. 😀

@JoffreyVerkadeNietVanDeKoekjes 5 лет назад

phew! I thought I needed to seriously do a speedtyping course haha

@kamaaladiin 4 года назад

@@JoffreyVerkadeNietVanDeKoekjes Even with Alien type of speed typing you wont be able to do that haha

@wanyi8761 3 года назад

hollywood level of typing speed lolol

@user-pb8df5ks4e Год назад

Lm pl

@dengelkemier 4 года назад

Where can one get an interactive Javascript console?

@senorzed6483 3 года назад

if you're using javascript as a web developer you can just link the javascript in your html like: " and then after you open the HTML file with your browser open the Inspector and there must be a Console in the Inspector section; else (if you're not a web dev) I don't know honestly, you can google it.

@robertogutierrez7305 2 года назад

What IDE is this? (and the font) I love to have a console like the one on the website :D

@rabbyhossain6150 2 года назад

// Normal function var a = 2 function display(){ var a = 3 console.log("From inside ", a) // 3 } display() console.log(a) // 2 // IIFE var a = 2; (function(){ var a = 3 console.log("From inside ", a) // 3 })() console.log(a) //2 what's the point here to use IIFE in your example?

@guliyevshahriyar Год назад

thx

@gigicaly 6 лет назад

what is that js compiler you are using?

@antonbodnia5788 5 лет назад

codepen

@arkahhhzzrisingto1071 2 года назад

wowo thnxd😀😀😃😃

@WebdevPath Год назад

I do not understand how did he assigned a function to the favNumber? The favNumber is not declared, how is it possible just take a random word and assign a function to it?

@christianherrero3778 4 года назад

I always thought that JS code was interpreted, not compiled.

@martinbozinovski 5 лет назад

var a = 2; function foo() { var a = 3 console.log(a); }; foo(); console.log(a); foo(); prints: 3 2 3 This is different from the thing you said. It is because of es6?

@oufcena5092 4 года назад

var a = 2; // Global scope variable function foo() { var a = 3 // Local scope variable console.log(a); }; foo(); // prints Local scope variable which is 3 console.log(a); // prints Global scope variable which is 2