@thi.ng/transducers-async/reduce.js

Async versions of various highly composable transducers, reducers and iterators

import { asyncIdentity } from "@thi.ng/api/async";
import { isReduced } from "@thi.ng/transducers/reduced";
async function reduce([init, complete, $reduce], ...args) {
  let acc = args.length < 2 ? await init() : args.shift();
  for await (let x of args[0]) {
    const y = await $reduce(acc, x);
    if (isReduced(y)) {
      acc = y.deref();
      break;
    }
    acc = y;
  }
  return await complete(acc);
}
const reducer = (init, rfn) => [init, asyncIdentity, rfn];
export {
  reduce,
  reducer
};