How Can I Import and Use Functions from External Files in Node.js?

Importing Functions from External Files in Node.js

In Node.js, it is possible to reuse code across multiple files by importing functions from one file into another. This approach allows for modular code organization and eliminates duplication.

Importing Functions from a Simple File

Let's consider the following scenario:

// app.js
var express = require('express');
var app = express.createServer();
app.set('views', __dirname + '/views');
app.set('view engine', 'ejs');
app.get('/', function(req, res){
  res.render('index', {locals: {
    title: 'NowJS + Express Example'
  }});
});

app.listen(8080);

To import functions from an external file, such as "tools.js," follow these steps:

1. Create an External File: Save the functions you want to import in a separate file, e.g., "tools.js."

2. Export Functions: In the external file, wrap the functions you want to make available in a module.exports object:

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

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3. Import Functions in Main File: In your main file (e.g., app.js), use the require() function to import the external file and access its exported functions:

   // app.js
   var tools = require('./tools');
   console.log(typeof tools.foo); // returns 'function'
   
   // You can now use the imported functions within your code

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By following these steps, you can effectively import functions from other files in Node.js, facilitating code reusability and modularity.

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