Waiting for initialization of the index?

I'm trying to create a lunr index and use it immediately. Another one of the issues showed how to use promises to do this, but IIUC this is also broken because the promise resolves the index before it is initialized:

function createLunrIndex(todos: Todo[], fieldNames: string[]) {
  return new Promise((resolve, reject) => {
    const idx = lunr(function () {
      fieldNames.forEach((fn) => {
        this.field(fn);
      });
      todos.forEach((todo) => {
        this.add(todo);
      });
    });
    resolve(idx);
  });
}

https://github.com/olivernn/lunr.js/issues/497

This is a stackblitz demo: https://stackblitz.com/edit/firefly-semantics-slice-entity-guide-fuodgg

Is there a way to wait for the initialization of the index?

Also asked about this on SO: https://stackoverflow.com/questions/72116666/waiting-for-the-lunr-index-to-initialize

olivernn / lunr.js

Waiting for initialization of the index? #515