Why does my Basic function is not working (in NodeJS)?

Question

I'm working on a nodejs project and there is a little problem. I know the problem is not hard to solve but i've been searching for hours now and still didn't figure out how to solve it :

var gs = require('./gs1');
if (uncompressedDigitalLinkInput != "") {
    try {
        this.error3="";
        console.log("Test");
        gs.myfunction();
    } 
    catch(err) {
        this.error3=err+"\n"+err.stack;
        return "";
    }
} 
else {
    return "";
}

And the problem is the line :

console.log("Test");
gs.myfunction();

Indeed, out of these two, only the console.log work. The other one doesn't.

Here is the code of "gs.myfunction"

class GS1DigitalLinkToolkit {
    function myfunction(){
        console.log('Function called');
    }
}
module.exports.myfunction = myfunction;

It tells me that "gs.myfunction is not a function". I have made sure that the require is the right path. So why it isn't working?

Answer 1

It happens because the method is callable only by an instance of GS1DigitalLinkToolkit. Two possible solutions can be:

1) Make the method static and export it as

class GS1DigitalLinkToolkit {
  static myfunction() {
      console.log('Function called');
  }
}

module.exports.myfunction = GS1DigitalLinkToolkit.myfunction

2) Import the class, make an instance and call the method on it

class GS1DigitalLinkToolkit {
    function myfunction(){
        console.log('Function called');
    }
}
module.exports.gsclass = GS1DigitalLinkToolkit;

and

var gs = require('./gs1');
if (uncompressedDigitalLinkInput != "") {
    try {
        this.error3="";
        console.log("Test");
        gs1 = new gs.gsclass();
        gs1.myfunction();
    } 
    catch(err) {
        this.error3=err+"\n"+err.stack;
        return "";
    }
} 
else {
    return "";
}

Answer 2

For your main file test.js :

var gs = require('./gs1')
gs.myfunction();

And this required file gs1.js :

function myfunction() {
  console.log('Function called');
}

module.exports.myfunction = myfunction;

You should get:

$ node ./test.js
Function called