Immutable version of Belt.Array.set?

jakehsiao · June 12, 2023, 9:18pm

The Belt.Array.set function modifies the original array in place.

But I need an immutable version that returns a new array without modifying the older one.

Is there an immutable set function in Belt API?

I know it is easy to implement one, but I wonder why Belt only has inplace version of set function.

woeps · June 13, 2023, 7:25am

I usually use Belt.Array.concat.

Depending on your use case, you could think about using a list.

namenu · June 21, 2023, 1:04am

Meanwhile in the rescript-core, there is ES2023 binding for immutable array set.

github.com

rescript-association/rescript-core/blob/3a45914f499d543ceb21a1fe89618afd09692e3a/src/Core__Array.resi#L249


      
          @send
          external sort: (array<'a>, ('a, 'a) => int) => unit = "sort"
          
          
@variadic @send
          external splice: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => unit = "splice"
          
          
@variadic @send
          external toSpliced: (array<'a>, ~start: int, ~remove: int, ~insert: array<'a>) => array<'a> =
            "toSpliced"
          
          
@send external with: (array<'a>, int, 'a) => array<'a> = "with"
          
          
/**
          `unshift(array, item)` inserts a new item at the start of the array.
          
          
Beware this will *mutate* the array.
          
          
See [`Array.unshift`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/unshift) on MDN.
          
          
## Examples
          ```rescript