Currently re-learning JS because I stopped JS for a while. ES6, wtf? Can someone explain the difference between the different ways of creating functions, and the difference between let and var. please? (Especially the function thing that’s got be fucked up)

There's youtube video explaining something about JS (3 hours long)
https://youtube.com/watch/...

About let vs var:
// var
for (var i = 0; i < 10; i++);
console.log(i); // will print last assignment of I

// let
for (let i = 0; i < 10; i++);
console.log(i); // error

let declares variable in it's own scope and that variable isn't visible outside.

{
let i = 1;
console.log(i); // 1
// new scope
{
let i = 2;
console.log(i); // 2
}
console.log(i); // 1
}

{
var i = 1;
console.log(i); // 1
{
var i = 2; // will replace I that was declared before
console.log(i); // 2
}
console.log(i); // 2
}

@irene I didn't watched him myself yet.

let is simply a way to declare variables with strict scoping.

The () => {
//stuff
}

is just a shorthand to create functions. That is very useful for callbacks, now you can simply write

someFunction(() => {
//callback
});

instead of

someFunction(function() {
//callback
}});

Function:

function Obj () { console.log(this); }
new Obj(); // his "this" points to himself.

Arrow function:

// creates anonymous function, you can't give him a name with arrow statement
var Obj = () => { console.log(this); }
new Obj(); // error, Obj is not a constructor
Obj(); // this points to Window or outer scope.

And arrow function doesn't have his own arguments list.

@Pogromist thx

You'll love it once get used to it, I promise

@ihatecomputers thx

@Pogromist that 'var'-example: Javascript does THAT? Literally every other language does proper variable scoping. Like, what the hell?

@ihatecomputers That joke took me a bit to resolve.

@PrivateGER Oops, I didn't mean to make a joke. I see that I missed a word... Is the joke that JS programs crash and burn every time you make a typo?

@ihatecomputers I took the use of "promise" as a joke. :D

@PrivateGER Haha, right 😀