calling a promise in "fire-and-forget" fashion but surprisingly subsequent code wasn't called

async-gotchas1.ts

// assume just this and you don't have access to its source code
let doAsyncThing: () => Promise<void>;

// another async fn - eg. logging, GA reporting
const doAsyncThingSafe = (): Promise<void> =>
  new Promise((resolve, _reject) => {
    console.log('🎉did <this> where <this = always needs to be done>🚀');
    resolve();
  });

let unfriendlyOneWhoseSignatureDoesNotIndicateIFiredAndForgotAPromise = () => {
  doAsyncThing();
};

let iCalledAndIRegrettedIt: () => Promise<void> = async () => {
  unfriendlyOneWhoseSignatureDoesNotIndicateIFiredAndForgotAPromise();
  await doAsyncThingSafe();
};

let friendlyOneWhoseSignatureIndicatesIFiredAndForgotAPromise = async () => {
  void doAsyncThing();
};

let iCalledAndIWasOk: () => Promise<void> = async () => {
  friendlyOneWhoseSignatureIndicatesIFiredAndForgotAPromise();
  await doAsyncThingSafe();
};

const main = async () => {
  doAsyncThing = doAsyncThingImpl1;
  try {
    console.log('running iCalledAndIRegrettedIt()');
    await iCalledAndIRegrettedIt();
  } catch (err) {
  } finally {
    console.log('done with iCalledAndIRegrettedIt()');
  }
  try {
    console.log('running iCalledAndIWasOk()');
    await iCalledAndIWasOk();
  } catch (err) {
  } finally {
    console.log('done with iCalledAndIWasOk()');
  }
  // "running iCalledAndIRegrettedIt()"
  // "done with iCalledAndIRegrettedIt()"    <--- <this> wasn't done 😢
  // "running iCalledAndIWasOk()"
  // "🎉did <this> where <this = always needs to be done>🚀"
  // "done with iCalledAndIWasOk()"
};

const doAsyncThingImpl1 = (): Promise<void> => {
  // to stand-in for analytics().logEvent() that was implemented in Java native code
  throw new Error('I interrupted your flow!');
};

main();

async-gotchas2.ts

// assume just this and you don't have access to its source code
let doAsyncThing: () => Promise<void>;

// another async fn - eg. logging, GA reporting
const doAsyncThingSafe = (): Promise<void> =>
  new Promise((resolve, _reject) => {
    console.log('🎉did <this> where <this = always needs to be done>🚀');
    resolve();
  });

let unfriendlyOneWhoseSignatureDoesNotIndicateIFiredAndForgotAPromise = () => {
  doAsyncThing();
};

let iCalledAndIRegrettedIt: () => Promise<void> = async () => {
  unfriendlyOneWhoseSignatureDoesNotIndicateIFiredAndForgotAPromise();
  await doAsyncThingSafe();
};

let friendlyOneWhoseSignatureIndicatesIFiredAndForgotAPromise = async () => {
  void doAsyncThing();
};

let iCalledAndIWasOk: () => Promise<void> = async () => {
  friendlyOneWhoseSignatureIndicatesIFiredAndForgotAPromise();
  await doAsyncThingSafe();
};

const main = async () => {
  doAsyncThing = doAsyncThingImpl2;
  try {
    console.log('running iCalledAndIRegrettedIt()');
    await iCalledAndIRegrettedIt();
  } catch (err) {
  } finally {
    console.log('done with iCalledAndIRegrettedIt()');
  }
  try {
    console.log('running iCalledAndIWasOk()');
    await iCalledAndIWasOk();
  } catch (err) {
  } finally {
    console.log('done with iCalledAndIWasOk()');
  }
  // "running iCalledAndIRegrettedIt()"
  // "🎉did <this> where <this = always needs to be done>🚀"
  // "done with iCalledAndIRegrettedIt()"
  // "running iCalledAndIWasOk()"
  // "🎉did <this> where <this = always needs to be done>🚀"
  // "done with iCalledAndIWasOk()"
};

const doAsyncThingImpl2 = async (): Promise<void> => {
  //                      ^^^^^ added this
  // demonstrates that async keyword transforms to Promise reject
  throw new Error('I interrupted your flow! 2');
};

const doAsyncThingImpl1 = (): Promise<void> => {
  // to stand-in for analytics().logEvent() that was implemented in Java native code
  throw new Error('I interrupted your flow!');
};

main();