Promise business/runtime logic error handling

promise-logic.ts

async function findUser(id: number) {
  console.log('Getting user...');
  
  await sleep(1000);
  
  // Mocked out API
  if(id === 999) {
    return [new Error('User not found'), undefined]
  }

  if(id === 1) {
    return [undefined, {
      name: 'Bilbo Baggins',
    }]
  }
  
  return Promise.reject('Something bad happened');
}

async function getUser() {
  try{
    const [userNotFound, user] = await findUser(1); 
    // User is found
    console.log('User found?', user);
  } catch(err) {
    throw err;
  }
  
  try{
    const [userNotFound, user] = await findUser(999);
    // User is not found
    console.log('User found?', userNotFound);
  } catch(err) {
    throw err;
  }
  
  try{
    const [userNotFound, user] = await findUser('No chance of working');
    // Runtime error
  } catch(err) {
    // throw new Error(err);
    console.error(err);
  }
}

getUser();

async function sleep(ms: number) {
  return new Promise((resolve)=> {
    setTimeout(resolve, ms);
  });
}