javascript - In express.js, when I use promises, do I need to include reject() in the executor? -

in situation not deal reject, must include reject in promise executor?

for example:

 new promise ((res)=>{    res(a);  }) 

if know promise never rejected, adding rejection handler not necessary. e.g. it's obvious never rejected , adding rejection handler plain silly:

promise.resolve("abc")     .then(result => console.log(result)); 

in other cases, not providing rejection handler pretty same not wrapping error-throwing piece of code in try-catch. might intentional, of course, bear in mind node.js treat unhandled promise rejections if uncaught errors: terminating node.js process. that's says on console when unhandled promise rejection occurs:

(node:7741) deprecationwarning: unhandled promise rejections deprecated. in future, promise rejections not handled terminate node.js process non-zero exit code.

so, summing up:

• skip rejection handlers when know fact rejection impossible,
• skip rejection handlers when require application terminated upon rejection (in future versions of node.js),
• write rejection handlers in other cases.

edit (the question became clearer after edits made, hence update answer):

as including reject() call in promise executor, no, not need add it. again though, have make sure internal logic guarantees resolve() called.