Assignments

JavaScript let assignment

Starting out with the basics, lets take a look at assigning values to variables. In JavaScript that’s going to look like:

let val : number = 5;

Elixir has a slightly more direct version:

val = 5

few notes

• no keyword for variable declarations in elixir - in this case let
• no type options for declaring variables - it is ALWAYS(mostly) an implicit declaration
• no semi-colons

JavaScript const assignment

In JavaScript, if you want a variable to stay the same value, slap a const keyword on it:

const val : number = 5;

Elixir:

val = 5

Wait, What?

Yep. You’re reading that correctly - elixir has the same declaration no matter what. The reasoning for this is all variables in elixir are immutable i.e. they can’t be changed, or this is what is advertised. Ergonomically variables in elixir will function similar to how let works in JavaScript, but behind the scenes elixir makes a copy of a variable, discards the old value, and assigns the new one. This alleviates mutability concerns, but won’t give you the familiar interpreter errors you’re using to seeing with const. Let me see if I can hack together an example:

val = 5

val = val + 1 #discards the old version of `val`, and creates a new variable named `val` with a value of 6

I’ve seen this described as labeling by some internet strangers, i.e. the label val represents the number 5, then the label val represents the number 6 after the second assignment. YMMV, my recommendation is to keep it simple and think about it however fits.

Conclusion

Not much to see here. Lets move into each language’s type system to get an idea of what all can be assigned to a variable.

Basic Types