CODEWITHSUNDEEP
javascriptnode.jsrequire
Ali hasan Galib
Ali hasan Galib

Reputation: 43

JavaScript calling function from external file gives .is not a fuction error, how can I fix this?

So, while I was using this require('fileName.js') to add an external JavaScript file to my main index.js file.

In the index.js

const caltor = require('./calculate.js');

console.log(caltor.adding(5,7));

In my calculate.js

function adding (i,y){
        return i+y;
}

BTW I am using nodejs to execute.

The error says:

console.log(caltor.adding(5,7));
                   ^
TypeError: caltor.adding is not a function

Upvotes: 1

Views: 391

Answers (2)

FZs
FZs

Reputation: 18619

Node.js modules don't automatically export their top-level scope variables/functions.

To export a value, you have two ways:

  • Add it to the exports object

    Node modules have a predefined variable exports, whose value is exported. Add your function to it:

    function adding (i,y){
  return i+y;
}

exports.adding = adding

    const caltor = require('./calculate.js');

console.log(caltor.adding(5,7));

    You can also export multiple values this way, just be sure to giv them a different name:

    function adding (i,y){
  return i+y;
}

exports.adding = adding

function subtracting (i,y){
  return i-y;
}

exports.subtracting = subtracting 

    const caltor = require('./calculate.js');

console.log(caltor.adding(5,7));
  console.log(caltor.subtracting(5,7));

  • Providing a "default" export by assigning to module.exports

    If you want to export a single value, you can assign it to module.exports. In this case, it becomes the value returned by require.

    Note that after assigning module.exports, defining a property on the exports variable will no longer work. Neither will assigning to exports varible export anything.

    function adding (i,y){
  return i+y;
}

module.exports = adding

    const adding = require('./calculate.js');

console.log(adding(5,7));

Upvotes: 2

lastmaj
lastmaj

Reputation: 326

You need to export the function 'adding' in your 'calculate.js' file.

module.exports = adding;

in your index.js file, no need to call caltor.adding() (Assuming that you only export one function from 'calculate.js').

console.log(caltor(5,7));

Upvotes: 3

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