@thi.ng/rstream/resolve.js

Reactive streams & subscription primitives for constructing dataflow graphs / pipelines

import { State } from "./api.js";
import { __optsWithID } from "./idgen.js";
import { LOGGER } from "./logger.js";
import { Subscription } from "./subscription.js";
const resolve = (opts) => new Resolver(opts);
class Resolver extends Subscription {
  outstanding = 0;
  fail;
  constructor(opts = {}) {
    super(void 0, __optsWithID("resolve"));
    this.fail = opts.fail;
  }
  next(x) {
    this.outstanding++;
    x.then(
      (y) => {
        if (this.state < State.DONE) {
          this.dispatch(y);
          if (--this.outstanding === 0) {
            this.done();
          }
        } else {
          LOGGER.warn(`resolved value in state ${this.state} (${x})`);
        }
      },
      (e) => {
        if (this.fail) {
          this.fail(e);
        } else {
          this.error(e);
        }
      }
    );
  }
  done() {
    const pstate = this.parent?.getState();
    if ((pstate === State.DONE || pstate === State.UNSUBSCRIBED) && this.outstanding === 0) {
      super.done();
    }
  }
}
export {
  Resolver,
  resolve
};