Promise - unhandled rejection warning has been thrown, although the rejection seems to be handled #1208

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1. vsemozhetbyt

   added

   question

   on Apr 11, 2018
2. ryzokuken commented on Apr 11, 2018

   

   ryzokuken

   on Apr 11, 2018

   Last edited by ryzokuken

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   @user8322 no question is noobish, and if it's troubling you then you should ask out without thinking too much about it :)

   Regarding 2 and 3, the unhandled warning came up because it was, in fact, not handled properly, because you tried handling success and failure at different statements. The correct code would be:

   'use strict';
   
   var a = new Promise((res, rej) => {
     rej(123);
     console.log('not ok');
   });
   
   a
     .then(() => console.log(1))
     .catch(a => console.log(a));
   
   // or just .then(...).catch(...) on the same line, but this way it's more readable

   and indeed, this work. See for yourself.

   Regarding 1, this happens because of how Node.js works and it's internals (as well as v8's). To get started with promises (regarding syntax and internals), try out nodeschool's workshop, "Promise it won't hurt" at https://github.com/stevekane/promise-it-wont-hurt
4. ghost closed this as completedon Apr 11, 2018