How Can I Include Functions from External Files in Node.js?

Including Functions from External Files in Node.js

When working with multiple JavaScript files in Node.js, there may be a need to utilize functions defined in one file within another. This can be achieved through the use of modules, allowing developers to encapsulate and reuse functionality.

Consider the following scenario: an application with a file called app.js and a separate file named tools.js containing helper functions. The goal is to import these functions into app.js for use.

Including Functions without Modules

One straightforward approach is to expose the desired functions in tools.js for access by other files. This can be achieved by assigning the functions to the module.exports object:

// tools.js
module.exports = {
  foo: function () {
    // ...
  },
  bar: function () {
    // ...
  }
};

In app.js, the functions can be imported using the require() function:

// app.js
var tools = require('./tools');
tools.foo(); // Calls the foo function

Including Functions Using Modules

An alternative approach is to turn tools.js into a module. Modules are self-contained units that can encapsulate functionality and expose specific interfaces. To create a module, use the module.exports syntax in tools.js:

// tools.js
module.exports = {
  foo: function () {
    // ...
  },
  bar: function () {
    // ...
  }
};

In app.js, require the module using the following syntax:

// app.js
var tools = require('./tools');
tools.foo(); // Calls the foo function

By following either of these approaches, it is possible to include functions from an external file in Node.js, allowing for code organization and reuse.

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