async constructor functions in TypeScript?

Issue

I have some setup I want during a constructor, but it seems that is not allowed

no async const

Which means I can’t use:

await

How else should I do this?

Currently I have something outside like this, but this is not guaranteed to run in the order I want?

async function run() {
  let topic;
  debug("new TopicsModel");
  try {
    topic = new TopicsModel();
  } catch (err) {
    debug("err", err);
  }

  await topic.setup();

Solution

A constructor must return an instance of the class it ‘constructs’. Therefore, it’s not possible to return Promise<...> and await for it.

You can:

  1. Make your public setup async.

  2. Do not call it from the constructor.

  3. Call it whenever you want to ‘finalize’ object construction.

    async function run() 
    {
        let topic;
        debug("new TopicsModel");
        try 
        {
            topic = new TopicsModel();
            await topic.setup();
        } 
        catch (err) 
        {
            debug("err", err);
        }
    }
    

Answered By – Amid

Answer Checked By – Pedro (AngularFixing Volunteer)

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