Node.js Export Module

The module.exports in Node.js is used to export any literal, function or object as a module. It is used to include JavaScript file into node.js applications. The module is similar to variable that is used to represent the current module and exports is an object that is exposed as a module.

Syntax:

• module.exports = literal | function | object

  Explanation: Here the assigned value (literal | function | object) is directly exposed as a module and can be used directly.

• module.exports.variable = literal | function | object

  Explanation: Here the assigned value (literal | function | object) is indirectly exposed as a module and can be consumed using the variable.

Example 1: Exporting Literals

• Create a file named as app.js and export the literal using module.exports.

  module.exports = "GeeksforGeeks";
• Create a file named as index.js and import the file app.js to print the exported literal to the console.

  const company = require("./app");
  console.log(company);
• Output:

  GeeksforGeeks

Example 2: Exporting Object

• Create a file named as app.js and export the object using module.exports.

  module.exports = {
    name: 'GeeksforGeeks',
    website: 'https://geeksforgeeks.org'
  }
• Create a file named as index.js and import the file app.js to print the exported object data to the console.

  const company = require('./app');
  
  console.log(company.name);
  console.log(company.website);
• Output:

  GeeksforGeeks
  https://geeksforgeeks.org
  

Example 3: Exporting Function

• Create a file named as app.js and export the function using module.exports.

  module.exports = function (a, b) {
    console.log(a + b);
  }
• Create a file named as index.js and import the file app.js to use the exported function.

  const sum = require('./app');
  
  sum(2, 5);
• Output:

  7

Example 4: Exporting function as a class

• Create a file named as app.js. Define a function using this keyword and export the function using module.exports.

  module.exports = function () {
    this.name = 'GeeksforGeeks';
    this.website = 'https://geeksforgeeks.org';
    this.info = () => {
      console.log(`Company name - ${this.name}`);
      console.log(`Website - ${this.website}`);
    }
  }
• Create a file named index.js and import the file app.js to use the exported function as a class.

  const Company = require('./app');
  
  const firstCompany = new Company();
  
  firstCompany.info();
• Output:

  Company name - GeeksforGeeks
  Website - https://geeksforgeeks.org
  

Example 5: Load Module from Separate Folders

const index = require('./models/lang/index.js');

Explanation: In the above example, the index.js file is under lang folder that is inside models folder. We can use the ./ to go to the root folder then we move relative to it.