Can We Call The Function Written In One Javascript In Another Js File

When writing JavaScript, you may wonder if it's possible to call a function written in one JavaScript file from another. The good news is, yes, you can certainly do that! This capability is essential for organizing your code, making it more modular, and easier to manage. Let's dive into how you can achieve this in your projects.

To call a function defined in one JavaScript file from another, you need to ensure that the function you want to call is accessible in the global scope or can be explicitly exported/imported using modules. The global scope allows variables and functions to be accessible from everywhere in your codebase.

Let's start with the global scope method. If your function is defined in `file1.js` and you want to call it in `file2.js`, you simply need to make sure that the function in `file1.js` is defined outside of any scope-specific block such as inside a `script` tag in an HTML file. This way, it becomes globally available for other JavaScript files to access and use.

For example, in `file1.js`, you have a function called `myFunction`:

function myFunction() {
   console.log("Hello from file1.js!");
}

To call `myFunction` from `file2.js`, you can just invoke it since it's in the global scope:

myFunction();

However, relying on the global scope for sharing functions across files may not always be the best practice, especially in larger projects. This is where modules come into play. With the introduction of ES6 modules, JavaScript provides a more structured and organized way of importing and exporting functionality across files.

To use modules, you need to export the functions you want to make accessible and import them in the files where you need to use them. In `file1.js`, you would export `myFunction`:

export function myFunction() {
   console.log("Hello from file1.js!");
}

And in `file2.js`, you would import and use `myFunction`:

import { myFunction } from './file1.js';

myFunction();

Make sure to use a server to run your code when working with modules, as most browsers don't support loading them from local files due to security restrictions. You can set up a simple local server using tools like `http-server` to test your code.

So, whether you prefer leveraging the global scope or embracing ES6 modules, calling a function from one JavaScript file in another is an achievable and powerful technique to enhance the modularity and maintainability of your codebase. Happy coding!