@thi.ng/rstream/pubsub.js

Reactive streams & subscription primitives for constructing dataflow graphs / pipelines

import { EquivMap } from "@thi.ng/associative/equiv-map";
import { unsupported } from "@thi.ng/errors/unsupported";
import { __optsWithID } from "./idgen.js";
import { LOGGER } from "./logger.js";
import { Subscription, subscription } from "./subscription.js";
const pubsub = (opts) => new PubSub(opts);
class PubSub extends Subscription {
  topicfn;
  topics;
  constructor(opts) {
    super(
      void 0,
      __optsWithID("pubsub", {
        xform: opts.xform
      })
    );
    this.topicfn = opts.topic;
    this.topics = new EquivMap(void 0, {
      equiv: opts.equiv
    });
  }
  /**
   * Unsupported. Use {@link PubSub.subscribeTopic} instead.
   */
  subscribe() {
    return unsupported(`use subscribeTopic() instead`);
  }
  /**
   * Unsupported. Use {@link PubSub.subscribeTopic} instead.
   */
  transform() {
    return unsupported(`use subscribeTopic() instead`);
  }
  subscribeTopic(topicID, sub, opts) {
    let t = this.topics.get(topicID);
    !t && this.topics.set(
      topicID,
      t = subscription(
        void 0,
        __optsWithID("topic", { closeOut: "never" })
      )
    );
    return t.subscribe(sub, opts);
  }
  transformTopic(topicID, xform, opts = {}) {
    return this.subscribeTopic(
      topicID,
      { error: opts.error },
      {
        ...opts,
        xform
      }
    );
  }
  unsubscribeTopic(topicID, sub) {
    const t = this.topics.get(topicID);
    return t ? t.unsubscribe(sub) : false;
  }
  unsubscribe(sub) {
    if (!sub) {
      for (let t of this.topics.values()) {
        t.unsubscribe();
      }
      this.topics.clear();
      return super.unsubscribe();
    }
    return unsupported();
  }
  done() {
    for (let t of this.topics.values()) {
      t.done();
    }
    super.done();
  }
  dispatch(x) {
    LOGGER.debug(this.id, "dispatch", x);
    this.cacheLast && (this.last = x);
    const t = this.topicfn(x);
    if (t !== void 0) {
      const sub = this.topics.get(t);
      if (sub) {
        try {
          sub.next?.(x);
        } catch (e) {
          if (!sub.error || !sub.error(e)) {
            return this.unhandledError(e);
          }
        }
      }
    }
  }
}
export {
  PubSub,
  pubsub
};