How Promise.allSettled works

Promise-allSettled-example.js

class CustomError extends Error {
  constructor(public data: any) {
    super(JSON.stringify(data));
  }
}

Promise.allSettled([
  Promise.resolve(33),
  new Promise((resolve) => setTimeout(() => resolve(66), 0)),
  99,
  Promise.reject(new Error('Message')),
  Promise.reject(new CustomError({ foo: 'a data'})),
]).then((values) => {
  
  console.log('3 is CustomError', values[3].reason instanceof CustomError);
  console.log('4 is CustomError', values[4].reason instanceof CustomError);
  console.log('4 is Error', values[4].reason instanceof Error);
  throw new Error('Show allSettled Catch')
}).catch(errors => {
  // Only show this if you throw an error in the Then
  console.log('Catch')
  console.error(errors)
});