AsyncIterator

Bindings to async iterators, a way to do async iteration in JavaScript.

See async iterator protocols on MDN.

The type representing an async iterator.

next(asyncIterator)

Returns the next value of the iterator, if any.

See async iterator protocols on MDN.

Examples

• A simple example, getting the next value:

RESCRIPT
@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"
let {AsyncIterator.done, value} = await asyncIterator->AsyncIterator.next

• Complete example, including looping over all values:

RESCRIPT
// Let's pretend we get an async iterator returning ints from somewhere.
@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"


let processMyAsyncIterator = async () => {
  // ReScript doesn't have `for ... of` loops, but it's easy to mimic using a while loop.
  let break = ref(false)

  while !break.contents {
    // Await the next iterator value
    let {value, done} = await asyncIterator->AsyncIterator.next

    // Exit the while loop if the iterator says it's done
    break := done

    // This will log the (int) value of the current async iteration, if a value was returned.
    Console.log(value)
  }
}

forEach(iterator, fn) consumes all values in the async iterator and runs the callback fn for each value.

See iterator protocols on MDN.

Examples

RESCRIPT
// Let's pretend we get an async iterator returning ints from somewhere.
@val external asyncIterator: AsyncIterator.t<int> = "someAsyncIterator"

await asyncIterator->AsyncIterator.forEach(value =>
  switch value {
  | Some(value) if value > 10 => Console.log("More than 10!")
  | _ => ()
  }
)