Imports & Exports

In this lesson, you'll learn about imports and exports in JavaScript, which are essential for organizing and managing code, especially in larger applications like those built with React. These features allow you to split your code into modules, making it more maintainable and reusable.

Understanding Imports and Exports

JavaScript modules allow you to break up your code into separate files, each responsible for a specific piece of functionality. This modular approach is particularly useful in frameworks like React, where components and utilities are often separated into different files.

Exporting from a Module

In JavaScript, you can export variables, functions, or objects from a module so that they can be used in other files. There are two main types of exports: named exports and default exports.

Named Exports

Named exports allow you to export multiple items from a module. Each item must be explicitly exported.

Example

const dogs = ['Bear', 'Fluffy', 'Doggo'];
const woof = (dogName) => console.log(`${dogName} says Woof!`);
const number = 5;
export { dogs, woof, number };

In this example, , , and are exported as named exports. You can export multiple items by listing them inside curly braces.

Default Exports

Default exports allow you to export a single item from a module. This is useful when a module primarily exports one thing.

Example

const onlyOneThing = 'test';
export default onlyOneThing;

Here, is exported as the default export. A module can have only one default export.

Importing into a Module

To use the exported items in another file, you need to import them. The syntax for importing depends on whether you're importing named exports or a default export.

Importing Named Exports

When importing named exports, you must use the same names as the exported items.

Example

import { dogs, woof, number } from './dogs.js';

console.log(dogs); // ['Bear', 'Fluffy', 'Doggo']
woof(dogs[0]); // 'Bear says Woof!'
console.log(number); // 5

Importing a Default Export

When importing a default export, you can choose any name for the imported item.

Example

import onlyOneThing from './test.js';
console.log(onlyOneThing); // 'test'

Conclusion

Understanding and is crucial for managing code in modern JavaScript applications. By using modules, you can keep your code organized, maintainable, and reusable. This modular approach is especially beneficial in frameworks like React, where components and utilities are often separated into different files. As you continue to build more complex applications, mastering imports and exports will become an essential part of your development toolkit.

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