TerminateWorker typing and errors

[studiosciences]

terminateWorker is documented in the README, but not included in the types. It can also error if the worker is not currently defined.

Expected behavior

• elk.terminateWorker() is a documented in types
• elk.terminateWorker() will not error if the worker is not defined (Not sure of the circumstances if this).

Screenshots
If applicable, add screenshots to help explain your problem.

ELK Version
0.8.2

Additional context
I want to terminate the layout rendering if the graph changes again before the rendering is complete. I'm not 100% sure that calling terminateWorker will not create a

  useEffect(() => {
    const elk = new ELK({
      workerUrl: webWorkerUrl,
    });

    elk
      .layout(elkInput)
      .then((elkOutput) => {
        // ...consume the elkOutput
      })
      .catch((err) => {
        throw new Error(err);
      });

    // Cancel the current job when input changes.
    return elk.terminateWorker; // <-- HERE
  }, [elkInput, webWorkerUrl]);

Workaround

    // Cancel the current job when input changes.
    return () => {
      // @ts-expect-error function is not documented
      if (elk.worker) elk.terminateWorker();
    };

[jlaneve]

+1 on this, was looking to do something similar but couldn't figure it out!

[saulshanabrook]

For anyone else coming here, I wanted to share a short snippet of how to use elkjs with custom termination based on an abort signal:

import ELKWorker from "elkjs/lib/elk-worker?worker&inline";

/**
 * Run an ELK layout that terminates if the signal is aborted.
 */
function layoutWithCancel(graph: ElkNode, signal: AbortSignal): Promise<ElkNode> {
  return new Promise((resolve, reject) => {
    // https://developer.mozilla.org/en-US/docs/Web/API/AbortSignal#implementing_an_abortable_api
    if (signal.aborted) {
      reject(signal.reason);
    }
    // I am doing something a little odd with the web worker so the source gets inlined, but you can create it however you want with a webworker.
    const elk = new ELK({
      workerFactory: () => new ELKWorker(),
      workerUrl: "",
    });
    signal.addEventListener("abort", () => {
      elk.terminateWorker();
      reject(signal.reason);
    });
    elk.layout(graph).then(resolve, reject);
  });
}

I am using this with Tanstack Query, which has support for aborting data fetching based on the signal.