javascript - How to differentiate between an unexpected error and planned rejection in angular promises? -

if understand correctly (promises api confusing), error occurred in promise suppressed, following code:

$http.post(...)     .then(data => {       if (data.nogood) {         return $q.reject();       } else {         // bug.         var = {};         return a.a.a > 3;       }     })     .catch(error => {       console.error('bad data');     }); 

is buggy, baddata not true if 'bad data' logged).

the desired behaviour me see console error upon every real runtime error, , leave handling rejections me. missing here? correct approach?

checking if error error on each catch block seems tedious.

unless rejection explicitly constructed error class or child, rejections can differentiated types.

.catch(error => {   if (!(error instanceof error))     console.error(error) }); 

exceptions $q promises handled $exceptionhandler service , logged default, if caught catch. without error instanceof error type check console.error(error) result in logging them twice.

despite reject , throw are used interchangeably of times, $q promises makes sense reject rejection reasons , throw errors error objects keep scheme working.