JavaScript Before Modules - Immediately Invoked Function Expressions (IIFE)

Before ES6 came out in 2015, JavaScript had not concept of modules and thus code outside of functions just became global. The immediately invoked function expression (or IIFE) was the solution to this.

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[sobanya_]

Now we just use it to add async in a place that’s not async

[walteredmond]

Use this a lot. Great explanation on it

[blackbeans]

Thanks this is very helpful for beginners, now i know what is the history of them...rather than using them two in the same time in my projects..

[PostMeridianLyf]

I did this once by mistake and changed my life

[k_gold]

So that means if I have a doStuff variable holding a string, it won't be substituted if I use the function doStuff in a module written like this?

[PraiseYeezus]

Wow, I remember trying to learn IIFE's at bootcamp and wondering why the hell it was relevant...this makes sense. Javascript used to suck!

[nanoguy]

You can also use the void operator before the function keyword then call it after the function block to do this, which I personally think is a bit cleaner. Good video!

[alibadra]

But why you would like to do that ? It's to make the function scope only the file it's in?

[evanbelcher]

I truly hate JS lol. I'm an Ionic app I'm very happy with using it, but still every time there's some pain point.

[Mr..Books]

iffe works but how do you call the doStuff... you actually need to strore the main func in a variable as iffe and return the doStuff func and have smth like
let main = (function() { return doStuff() {} })()
main.doStuff() // this works now

[davesharma]

But what if we want to execute the function again
Wouldn't that create a problem since iife can be only executed once

[NavroZ]

Looking at this makes me glad that I have not and never will use javascript.

[minerscale]

gosh Javascript is a crufty language hahaha, what a weird syntax. It gets the job done I guess. Hoping for wasm first class DOM manipulation some time in the future so we can choose to not use JS at all.

[jasonmurphy]

Sounds like JavaScript was unusable prior to 2015