Node JS - Calling a method from another method in same file

Question

I have this nodeJS code.

module.exports = {

  foo: function(req, res){
    ...
    this.bar(); // failing
    bar(); // failing
    ...
  },

  bar: function(){
    ...
    ...
  }
}

I need to call the bar() method from inside the foo() method. I tried this.bar() as well as bar(), but both fail saying TypeError: Object #<Object> has no method 'bar()'.

How can I call one method from the other?

@Danil foo is a request handler which is called from the router. — Veera, Sep 05 '12 at 04:16
Something is definitely changing the `this` context but the question is who? — ChaosPandion, Sep 05 '12 at 04:17
OK, tried `module.exports.foo()` and it works.. But will figure out why the context is missing.. — Veera, Sep 05 '12 at 04:20

timidboy · Accepted Answer · 2020-01-22T19:38:13.587

14

You can do it this way:

module.exports = {

  foo: function(req, res){

    bar();

  },
  bar: bar
}

function bar() {
  ...
}

No closure is needed.

edited Jan 22 '20 at 19:38

answered Sep 05 '12 at 04:24

timidboy

1,702
1
16
27

score 9 · Answer 2 · answered Mar 23 '17 at 22:46

9

The accepted response is wrong, you need to call the bar method from the current scope using the "this" keyword:

    module.exports = {
      foo: function(req, res){

        this.bar();

      },
      bar: function() { console.log('bar'); }
    }

answered Mar 23 '17 at 22:46

Nicolas Bonnici

423
4
11

score 4 · Answer 3 · answered Sep 05 '12 at 04:20

4

I think what you can do is bind the context before passing the callback.

something.registerCallback(module.exports.foo.bind(module.exports));

answered Sep 05 '12 at 04:20

ChaosPandion

77,506
18
119
157

score 2 · Answer 4 · answered Sep 05 '12 at 04:21

2

Try this:

module.exports = (function () {
    function realBar() {
        console.log('works');
    }
    return {

        foo: function(){
            realBar();
        },

        bar: realBar
    };
}());

answered Sep 05 '12 at 04:21

Lucas Green

3,951
22
27

score 1 · Answer 5 · edited Jan 16 '17 at 16:52

1

Try the following code. You can refer each function from anywhere (needs to import .js file)

function foo(req,res){
    console.log("you are now in foo");
    bar();
}
exports.foo = foo;

function bar(){
    console.log("you are now in bar");
}
exports.bar = bar;

edited Jan 16 '17 at 16:52

NikxDa

4,137
1
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48

answered Jan 16 '17 at 14:01

Chanaka Fernando

2,176
19
19

score 0 · Answer 6 · answered Apr 03 '13 at 19:36

0

Is bar intended to be internal (private) to foo?

module.exports = {
    foo: function(req, res){
        ...
        function bar() {
            ...
            ...
        }
        bar();     
        ...
    }
}

answered Apr 03 '13 at 19:36

user323774

400
3
9

score 0 · Answer 7 · answered Jan 15 '20 at 13:06

in Node js + Express, you can use this syntax in the same controller

//myController.js
exports.funA = () =>{

    console.log("Hello from funA!")

    //cal funB
    funB()

}

let funB = () =>{

    console.log("Hello from funB!")
}

make sure to use the let keyword before the function and call it with the () parentheses inside the main function

OUTPUT

App listening at http://localhost:3000
Hello from fun A!
Hello from fun B!

Node JS - Calling a method from another method in same file

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