How to use 'await' inside a sync function?

Question

I want to make an API like this:

class jsonReader {
  public async load()
  {
     // some code
  }
}

let reader = new jsonReader();

function foo(){
  await reader.load();
  // [ts] 'await' expression is only allowed within an async function.
}

How can I use Async/Await inside a synchronous function call?

Answer 1

You either make that function asynchronous as well and use await or use the promise from the returned function. All functions marked with async return Promise<T>. In your shared code the return type is Promise<void>, you can chain then to it.

function foo(){
  reader.load().then(() => /*your code here*/);
}