Node.js - Return Array from function

Question

I have a function that returns an array created with method myArray.push({"key":value})

In router file I did this, but it didn't work:

router.get('/:ID', function(req, res, next) {
    var myRenderArray = [];
    myRenderArray = auxFunctions.myArrayFunc(req.params.ID);
    res.render('myView', {title: 'title', myRenderArray});
});

If I put the whole function inside router file, and change the return statement for res.render('myView', {title: 'title', myRenderArray}); it works!

Resumed Function code:

module.exports.myArrayFunc = function myArrayFunc(ID){
        var myArray = [];
        var id = req.params.ID;
        var req1 = new dbConfig1.Request(); 
        var req2 = new dbConfig2.Request();


        req1.query(query1('foo', ID)) 
        .then(function (array1) { 
                req2.query(query2('foo', id, array1[0].fooId))         
                .then(function (array2) {
                   req1.query(query3(array1[0].fooId))         
                    .then(function (array3) {
                        req1.query(query4('foo', ID, array1[0].fooId))      
                        .then(function (array4) {
                            myArray.push({
                                'name1': key1,
                                'name2': key2,
                                'name3': key3,
                                'name4': key4,                                
                            });

                            return myArray;
                        })



                        .catch(function (err) { console.log('****** Error on query 4'); console.log(err); });
                    })
                    .catch(function (err) { console.log('****** Error on query 3'); console.log(err); });
                })
                .catch(function (err) { console.log('****** Error on query 2'); console.log(err); });
        })
        .catch(function (err) { console.log('****** Error on query 1'); console.log(err); });
    }

How can I do?

Thanks!

can you try this res.render('myView', {title: 'title', array: myRenderArray}); — dyaa
– dyaa, Commented Mar 27, 2017 at 15:02

Love-Kesh · Accepted Answer · 2017-03-28 06:25:48Z

1

You can't return from callback

  router.get('/:ID', function(req, res, next) {
    var myRenderArray = [];

    //use callback instead 
    auxFunctions.myArrayFunc(req.params.ID ,function(myRenderArray){

        if(myRenderArray){
         res.render('myView', {title: 'title', myRenderArray});
     }
 });

});


module.exports.myArrayFunc = function myArrayFunc(ID ,callback){
    var myArray = [];
    var id = req.params.ID;
    var req1 = new dbConfig1.Request(); 
    var req2 = new dbConfig2.Request();


    req1.query(query1('foo', ID)) 
    .then(function (array1) { 
        req2.query(query2('foo', id, array1[0].fooId))         
        .then(function (array2) {
           req1.query(query3(array1[0].fooId))         
           .then(function (array3) {
            req1.query(query4('foo', ID, array1[0].fooId))      
            .then(function (array4) {
                myArray.push({
                    'name1': key1,
                    'name2': key2,
                    'name3': key3,
                    'name4': key4,                                
                });

                //return using callback
                return callback(myArray);
            })



            .catch(function (err) { console.log('****** Error on query 4'); console.log(err); });
        })
           .catch(function (err) { console.log('****** Error on query 3'); console.log(err); });
       })
        .catch(function (err) { console.log('****** Error on query 2'); console.log(err); });
    })
    .catch(function (err) { console.log('****** Error on query 1'); console.log(err); });
}

answered Mar 28, 2017 at 6:25

Love-Kesh

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2 Comments

Sergi Nadal Over a year ago

Still not working. I put some console.log, and seems that the function don't execute.

Love-Kesh Over a year ago

try change module.exports.myArrayFunc to exports.myArrayFunc only where it is defined

rsp · Accepted Answer · 2017-03-27 15:07:00Z

1

The only relevant part of the code here is exactly what you didn't include in your question - the source code of the function that doesn't return the array. The only other relevant data is the error message. Without seeing that code or the error message I can only guess but you may be doing few things there: You may be using a global variable, or a variable in the outer scope, for the array and it gets shared between invocations. You may be using res or some other variable that is available in the request handler but not in that function. It's all speculation because you didn't include the source code of the function or the error message so it's impossible to give you any more detailed info.

answered Mar 27, 2017 at 15:07

rsp

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