CODEWITHSUNDEEP
javascriptnode.jsasynchronous
Lee Brindley
Lee Brindley

Reputation: 6512

NodeJs, does asynchronous function complete after api route has returned

My local tests find that the question is true.

Given the following code, where 'asyncOne' and 'asyncTwo' are asynchronous functions, if 'asyncTwo' completes before 'asyncOne' does 'asyncOne' still get time to finish execution? 

router.get("/", function (req, res, next) {

       asyncOne(function () {
            console.log("Completed asyncOne");
       });


       asyncTwo(function () {
            console.log("Completed asyncTwo");

            return res.json("Done.");
       });
});

Upvotes: 0

Views: 61

Answers (2)

Ильяс Гарифуллин
Ильяс Гарифуллин

Reputation: 378

Maybe you shoud call your functions like this:

router.get("/", function (req, res, next) {
  Promise.all[asyncOne(), asyncTwo()].then(() => {
     return res.json("Done.");
  });
});

or like this:

router.get("/", function (req, res, next) {
  asyncOne(function () {
   console.log("Completed asyncOne");
    asyncTwo(function () {
     console.log("Completed asyncTwo");
     return res.json("Done.");
    });
   });       
 });

Upvotes: 1

GiveMeAllYourCats
GiveMeAllYourCats

Reputation: 888

Yes all code will execute. But you cannot return res.json("Done."); in the asyncOne function, because a end response has already been sent.

If you would like a return to be called when both async functions are done you should checkout the async module. It's really great.

Upvotes: 1

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