Promise's second .then() not failing [duplicate]

Answer 1

Why does the second then() has its done handler called instead of the fail one?

Because you handled the error in the first then() of the chain already, making the promise resolve with the "First then: FAIL" string that you returned from it.

Is this a bug with Chrome?

No, that's how promises are supposed to work.

Do I need to resort to returning pre-resolved/rejected Promises from the .then handlers?

You can do that, yes. Other ways to trigger the second fail handler would be:

• Simply omit the first error handler:

  prom.then(function(done) {
      console.log("First handler: Done!: Argument: ", done);
      return "First then: DONE";
  }).then(function(done) {
      console.info("Second handler: Done!.  Argument: ", done);
  }, function(fail) {
      console.error("Second handler: Fail!.  Argument: ", fail);
  });
  

• Or rethrow an exception (that's similar to returning a rejected promise):

  prom.then(function(done) {
      console.log("First handler: Done!: Argument: ", done);
      return "First then: DONE";
  }, function(fail) {
      console.error("First handler: Fail!. Argument: ", fail);
      throw new Error("First then: FAIL"); // or: throw fail;
      // alternatively, you can return a rejected promise:
      return Promise.reject(new Error("First then: FAIL"));
  }).then(function(done) {
      console.info("Second handler: Done!.  Argument: ", done);
  }, function(fail) {
      console.error("Second handler: Fail!.  Argument: ", fail);
  });