async constructor functions in TypeScript?

Question

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

Which means I can't use:

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(); 

Answer 1

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);     } }