2 ms·

> the only addition that a beginner needs to know is that there is a new option that those two languages don't have which is pass by reference or pass by value

> the only addition that a beginner needs to know is that there is a new option that those two languages don't have which is pass by reference or pass by value I think anyone who's done anything beyond beginner JavaScript is going to understand the difference between pass by value and pass by reference, even if they don't call them that? function foo1( val : string ) { val = "hi" } function foo2( val : [string] ) { val[0] = "hi" } const bar : [string] = ["yo"]; foo1( bar[0] ); console.log( bar ); foo2( bar ); console.log( bar );

iterateoften 4y ago
The big difference when I use Rust is that in Rust every variable you accept in a function requires you to make that choice. Whereas JS it’s kind of chosen for you. In your example you had to go out of your way to do it. So just a bit more mental overhead for implementing libraries. But not a huge deal.
ptero 4y ago
It is not just the abstract knowledge of the difference, but the fact that "let b = a" makes a undefined and, especially, some comfort with a Rust-ic way of dealing with this. My 2c.
gavinray 4y ago
> I think anyone who's done anything beyond beginner JavaScript is going to understand the difference between pass by value and pass by reference, even if they don't call them that? Pass-by-reference is a concept that is unfamiliar to many (most?) modern JS/TS developers, as the common idiom is that you "return" a new object or value at the end of your function. If you want to update a value in an existing object, you pass it by value and return a clone of it with the updated values Performance doesn't matter, you can do the most pants-on-head-stupid thing you can imagine, or have your frontend page/component be re-rendering 20 times on every state change, and it makes no perceptible difference. (This has been my experience) It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them
- petesergeant 4y ago
  > It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them If you pass an array to a function in JavaScript, then any changes you make to it will mutate the version the caller has.

iterateoften 4y ago

The big difference when I use Rust is that in Rust every variable you accept in a function requires you to make that choice. Whereas JS it’s kind of chosen for you. In your example you had to go out of your way to do it. So just a bit more mental overhead for implementing libraries. But not a huge deal.

ptero 4y ago

It is not just the abstract knowledge of the difference, but the fact that "let b = a" makes a undefined and, especially, some comfort with a Rust-ic way of dealing with this. My 2c.

gavinray 4y ago

> I think anyone who's done anything beyond beginner JavaScript is going to understand the difference between pass by value and pass by reference, even if they don't call them that? Pass-by-reference is a concept that is unfamiliar to many (most?) modern JS/TS developers, as the common idiom is that you "return" a new object or value at the end of your function. If you want to update a value in an existing object, you pass it by value and return a clone of it with the updated values Performance doesn't matter, you can do the most pants-on-head-stupid thing you can imagine, or have your frontend page/component be re-rendering 20 times on every state change, and it makes no perceptible difference. (This has been my experience) It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them

petesergeant 4y ago
> It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them If you pass an array to a function in JavaScript, then any changes you make to it will mutate the version the caller has.