@thi.ng/rstream/transduce.js

Reactive streams & subscription primitives for constructing dataflow graphs / pipelines

import { isReduced } from "@thi.ng/transducers/reduced";
const transduce = (src, xform, rfn, init) => {
  let acc = init !== void 0 ? init : rfn[0]();
  let sub;
  return new Promise((resolve, reject) => {
    sub = src.subscribe(
      {
        next(x) {
          let _acc;
          try {
            _acc = rfn[2](acc, x);
          } catch (e) {
            reject(e);
            return;
          }
          if (isReduced(_acc)) {
            resolve(_acc.deref());
          } else {
            acc = _acc;
          }
        },
        done() {
          resolve(acc);
        },
        error(e) {
          reject(e);
          return false;
        }
      },
      { xform }
    );
  }).then(
    (fulfilled) => {
      sub.unsubscribe();
      return fulfilled;
    },
    (rejected) => {
      sub.unsubscribe();
      throw rejected;
    }
  );
};
export {
  transduce
};