nodejs function declaration

Question

I am declaring a function like so in a file:

File1:
    module.exports = {
       function1: function(callback){
          //do some work
       },
    }

In another file if i import File1 and call file1.function1 the function runs and I get the result.

Although, if I am in File1 and declare another function:

module.exports = {
    function1: function(callback){
          //do some work
    },
    function2: function(callback){
        var result = function1...
    }
}

In this case I am getting function1 is not defined.

Why is this happening? shouldn't it be called the someway independent of where the call is being made?

Answer 1

The problem is that you are trying to access function1 from the wrong scope. There is no defined "function1" variable in your scope. You only have module.exports.function1

const exportObject = {
    function1: function(callback){
          //do some work
    },
    function2: function(callback){
        var result = exportObject.function1... // or this.function1
    }
}

module.exports = exportObject;

Should work

UPDATE: a few more examples:

function1() {
   // this will be executed by example2
}

var example3 = {
   function1: function () {
      // this will be executed by example3
   }
}
const exportObject = {
    function1: function(callback){
        // This will be executed by example1
    },
    function2: function(callback){
        // example1
        var result = exportObject.function1() // or this.function1()
        // example2
        var result = function1()
        // example3
        var result = example3.function1()
    }
}

module.exports = exportObject;

Answer 2

function1 is not a variable.

It is a property of the object you assigned to module.exports .

Compare to this:

 var foo = { bar: 1 } console.log(bar); 

bar is a property of foo , not a variable in its own right.

You have to treat it as such.

 var foo = { bar: 1 } console.log(foo.bar); 

The same is true of function1 .

You need to access it as object property:

var result = module.exports.function1();

Answer 3

If you create a function module.exports.function1 in File 1, the way you access it in File 1 is by saying module.exports.function1 . It's a bit long winded. Alternatively, you can create it like this in File 1:

 var function1 = function() {...};
 module.exports.function1 = function1;

 function1();

You can continue to use function1 in File 2:

 var file1 = require('./file1');
 file1.function1();