Angular / TypeScript - Call a function after another one has been completed

Question

I would like to call f2 after f1 has been completed. f1 function can be synchronous or asynchronous.

Answer 1

If f1 is synchronous, there is nothing special to do:

global() {
    f1();
    f2();
}

If f1 is asynchronous and return an Observable, use Rxjs operator, like concatMap:

global() {
    f1().concatMap(() => f2());
}

If f1 is asynchronous and return a Promise, use async/await:

async global() {
    await f1();
    f2();
}

If f1 is asynchronous and return a Promise (alternative):

global() {
    f1().then(res => f2());
}