How can I export module pattern function to another JavaScript file

Question

I have two JavaScript files and would like to export the file with module pattern to another file. The file with module pattern, I would like to export only public members. When I try to execute the test, it says that "Calculator is not a constructor".

file: calculator.js

var Calculator = function(){
    var total = null;

    return {      
        add: function(x,y){
            total = x + y; 
        },

        getTotal: function(){
            return total;
        };

        display: function(){
            console.log(total);
        }
    }
}

second file: testCalculator.js

const calculatorObj = require('calculator.js');

describe("Calculator test suite", function(){
    var calculatorObj = new Calculator();

    it('Verify sum method', function() {        
        try{
            calculatorObj.add(5,5);                

            //assertive
            expect(10, calculatorObj.getTotal());
        }
        catch(err)
        {
            alert(err);
        }
    });
});

You forget to export your calculator: module.exports = function(){ — Drag13
– Drag13, Commented Aug 2, 2020 at 7:44
do I have to list all the function names that I want to export? and in "testCalculator.js" file, do i need to use "import" or "require()" — Phil
– Phil, Commented Aug 2, 2020 at 7:48

Drag13 · Accepted Answer · 2020-08-02 08:57:30Z

2

It is not working, because you need to export something before consuming it.

Add this code to make it work

module.exports = function(){
    var total = null;

    return {      
        add: function(x,y){
            total = x + y; 
        },

        getTotal: function(){
            return total;
        };

        display: function(){
            console.log(total);
        }
    }
}

do I have to list all the function names that I want to export?

Yes, you have to export all things you want to import later. Or you can export one single object with all code you need.

do i need to use "import" or "require()"

For Node.js, require is common practice. Latest Node.JS supports import construction, but, at least for now, using require is preferable.

For browsers, you will use import notation.

And your function is not a classical constructor, please, take a look into the class notation

edited Aug 2, 2020 at 8:57

answered Aug 2, 2020 at 7:48

Drag13

6,0281 gold badge22 silver badges44 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

Phil Over a year ago

when I have only one JavaScript fille "calculator", i was able to do something like "let cal = new Calculator(); cal.add(5,5); cal.display();

Drag13 Over a year ago

When you have 1 file, you don't need to do import/export. You are free to use all written code. But this is not something good, really. File with 10 000 lines is a big ball of mood.

Phil Over a year ago

thanks. After following your suggestion, I can see the public members when debugging the code, but somehow intelliSense does not show the members.

Drag13 Over a year ago

Use typescript or jsDoc if you want to have good IntelliSense jsdoc.app/tags-example.html

Phil Over a year ago

thanks, i will check them out. I'm using Visual Studio Code though.

Collectives™ on Stack Overflow

How can I export module pattern function to another JavaScript file

1 Answer 1

5 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

5 Comments

Your Answer

Sign up or log in

Post as a guest

Related