What Is "Export Default" In Javascript?

What is “export default” in JavaScript?

When working with JavaScript modules, you might have come across the term “export default”. In this blog post, we will explore what “export default” means and how it can be used in your JavaScript code.

“export default” is a syntax feature introduced in ECMAScript 6 (ES6) that allows you to export a single value or a module as the default export. It is commonly used when you want to export a single function, class, or object as the main export of a module.

Let’s take a look at some examples to understand how “export default” works:

Example 1: Exporting a Function

In this example, we have a module named “mathUtils.js” that exports a function named “add”. We can use “export default” to export the “add” function as the default export of the module:


// mathUtils.js
const add = (a, b) => a + b;
export default add;

To import the default export in another module, you can use any name you prefer:


// app.js
import myAddFunction from './mathUtils.js';
console.log(myAddFunction(2, 3)); // Output: 5

Example 2: Exporting an Object

In this example, we have a module named “config.js” that exports an object containing configuration values. We can use “export default” to export the configuration object as the default export of the module:


// config.js
const config = {
  apiUrl: 'https://api.example.com',
  apiKey: 'YOUR_API_KEY'
};
export default config;

To import the default export in another module, you can use any name you prefer:


// app.js
import myConfig from './config.js';
console.log(myConfig.apiUrl); // Output: https://api.example.com

It’s important to note that a module can have only one default export. However, you can still have named exports alongside the default export.

Here’s an example of a module with both a default export and named exports:


// utils.js
export const multiply = (a, b) => a * b;
export const divide = (a, b) => a / b;
export default multiply;

To import the default export and named exports in another module, you can use the following syntax:


// app.js
import myMultiplyFunction, { divide } from './utils.js';
console.log(myMultiplyFunction(2, 3)); // Output: 6
console.log(divide(10, 2)); // Output: 5

In conclusion, “export default” is a powerful feature in JavaScript that allows you to export a single value or module as the default export. It simplifies the importing syntax and provides a convenient way to export the main functionality of a module. Whether you’re exporting a function, class, or object, “export default” can be a useful tool in your JavaScript projects.

Now that you understand what “export default” means in JavaScript, you can start using it in your own code to enhance the modularity and reusability of your modules.

What Is “Export Default” In Javascript?