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Mastering Default and Named Exports in JavaScript Modules

Understanding the “export default was not found” error

When working with JavaScript, you may come across an error message that says “export default was not found.” This error occurs when the JavaScript module you are importing is missing a default export. This can happen for a few different reasons.

One reason for this error may be that you are importing a named export without using curly braces. When you import a named export, you need to surround it with curly braces.

If you forget to do this, JavaScript assumes you are trying to import a default export and will throw an error if one does not exist. Another reason for this error could be that the module you are importing has a named export instead of a default export.

In this case, you will need to use a named import instead of a default import. To fix the “export default was not found” error, you need to make sure you are importing the correct type of export.

If you are importing a default export, use the `default` keyword. If you are importing a named export, use curly braces around the export name.

Using default and named exports in JavaScript

JavaScript modules can be exported in two different ways: with a default export or with named exports. Default exports are often used for modules that only have one main function or object, while named exports are used for modules that have multiple functions or objects.

Syntax for default export

To export a variable with a default export, you need to use a variable declaration and the `export default` keywords. Here is an example:

“`

const myVar = “Hello World”;

export default myVar;

“`

This code exports the `myVar` variable as a default export.

You can also use a single line to declare and export a variable with a default export, like this:

“`

export default “Hello World”;

“`

Syntax for named exports

To export multiple variables with named exports, you need to use the `export` keyword before each variable declaration. Here is an example:

“`

export const myVar1 = “Hello”;

export const myVar2 = “World”;

“`

This code exports `myVar1` and `myVar2` as named exports.

Mixing default and named exports

When using both default and named exports in a JavaScript module, it’s important to maintain consistency in your imports and exports. If you export a default export, you should import it with the `default` keyword.

If you export named exports, you should import them with curly braces. Here is an example of a module that uses both default and named exports:

“`

const myVar1 = “Hello”;

const myVar2 = “World”;

const myVar3 = “Goodbye”;

export default myVar1;

export { myVar2, myVar3 };

“`

To import the default export, use the `default` keyword:

“`

import myVar1 from “./myModule”;

“`

To import the named exports, use curly braces:

“`

import { myVar2, myVar3 } from “./myModule”;

“`

By maintaining consistency in your imports and exports, you can avoid the “export default was not found” error and ensure that your code is easy to understand and maintain.

Conclusion

By understanding the differences between default and named exports in JavaScript, you can write more modular, maintainable code. Remember to use the correct syntax for each type of export and to maintain consistency in your imports and exports.

With these tips, you can avoid common errors and write cleaner, more effective JavaScript modules.

Additional Resources

If you are interested in learning more about default and named exports in JavaScript, there are many resources available online that can help you deepen your understanding and improve your skills.

Related Tutorials for Further Learning

1. MDN Web Docs – Import and Export

MDN is a trusted source of documentation for all things web development, and their guide to import and export in JavaScript is a great place to start learning about module syntax and exports.

The guide covers both default and named exports, how to import them, and how to mix and match them in your code. 2.

JavaScript Info – Export and Import

JavaScript Info provides a comprehensive tutorial on exporting and importing modules in JavaScript. The guide covers a variety of scenarios for exporting and importing variables, functions, classes, and even entire modules.

With detailed explanations and examples, this tutorial is a great resource for developers of all levels. 3.

ES6 In Depth – Default exports

ES6 In Depth is a series of articles by Mozilla that explore the new features and functionality introduced in ECMAScript 6 (ES6). This article focuses specifically on default exports, explaining how and why to use them in your code.

The article also covers some of the nuances and edge cases you may encounter when working with default exports. 4.

ES6 In Depth – Named exports

Another article from ES6 In Depth, this tutorial focuses on named exports in JavaScript. The article covers how to export multiple variables and functions, as well as how to alias named exports and how to selectively import named exports.

5. W3Schools – JavaScript Modules

W3Schools is a popular resource for learning web development skills, and their guide to JavaScript modules is a great starting point for beginners.

The guide covers both default and named exports, how to import and use modules in your code, and how to use modules in HTML documents. 6.

Egghead – Understanding ES6 Modules

This video tutorial from Egghead provides a comprehensive overview of ES6 modules, including how to export objects and classes, how to use default exports, and how to import modules in your code. The video also covers some of the common pitfalls you may encounter when working with modules and how to avoid them.

Conclusion

In conclusion, if you want to become proficient in JavaScript module syntax and exports, there are many resources available to help you learn. From documentation to tutorials to video courses, there is no shortage of information on this topic.

Choose the resources that work best for your learning style and skill level, and don’t be afraid to experiment with different types of exports and import syntax. With some practice and a solid understanding of module exports, you can write more modular, maintainable code that is easy to work with and scale.

To summarize, JavaScript’s export and import features are essential to writing modular and scalable code in the language. The article primarily covers the difference between default and named exports, their syntax, and combining both types of exports in a module.

Understanding their distinctions and how to work with them is crucial to writing effective code, improving maintainability, and avoiding common errors. The article also provides a list of additional resources that summarize and deepen the knowledge of these vital JavaScript features.

Ultimately, taking the time to learn and master these functionalities can transform your approach to the programming language and enhance your productivity as a developer.

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