CODEWITHSUNDEEP
node.jsexpresssynchronous
Mohammed Gadiwala
Mohammed Gadiwala

Reputation: 2073

Why isn't next function in my express code working properly?

So basically I am trying to carry out function synchronously using next but Its not happening synchronously: Route.JS

 router.post('/era',function(req,res,next){
        console.log("got request");

    controlleri.book(req,res,next);
    booking_controller.book(req,res);
    console.log("done in server.js");
    next();

});

controlleri.book and booking_controller.book both have database calls but Inspite of adding next() in controlleri.book, booking_controller.book starts executing before next being called in the first function. Tell me if both functions are needed.

Edit:

Tried using async library still its not going synchrounosly Code:

router.post('/era',function(req,res){
    console.log("got request");

async.series([

function(callback){
    console.log("hi");
    controlleri.book(req,res);
    callback(null);
},
function(callback){
    console.log("hias");
    booking_controller.book(req,res);
    callback(null);
}

]);

Second function begins before completing First one

Upvotes: 1

Views: 104

Answers (2)

Himani Agrawal
Himani Agrawal

Reputation: 1272

Use aync library for doinf operations syncronously.

next() is a middleware which tells that the request shouldn't be returned but there are more functions to be applied on the request.The functions it gets to operate are performed asynchronously because that's node's default behaviour.

async.series([
    controlleri.book(callback){
        // do some stuff ...
        callback(null, 'one');
    },
    booking_controller.book(callback){
        // do some more stuff ...
        callback(null, 'two');
    }
],
// optional callback
function(err, results){
    // results is now equal to ['one', 'two']

});

async.series takes an array of functions to be performed in order (synchronously). The callback passed in each function is mandatory.

Upvotes: 0

nem035
nem035

Reputation: 35501

Both of your functions take req, res and next as their arguments which is a signature for a middleware function. Further, express middleware is executed in order. Why not just make each of your functions into their own middleware and in the execution order you need them in?

// POST executes controlleri.book
// then booking_controller.book,
// then the log code
router.post('/era', controlleri.book, booking_controller.book, function(req, res, next) {
  console.log("done in server.js");
});

This way, next within controlleri.book will be booking_controller.book, and next in booking_controller.book will be the last method that logs "done in server.js"

Upvotes: 1

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