Resolving webpack Issues: Why Can't It Find React with Custom Entry Points?

Описание: Discover the solution to webpack's difficulty in locating React when a custom entry point is used. Learn how to configure your project correctly to avoid common pitfalls.
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Resolving webpack Issues: Why Can't It Find React with Custom Entry Points?

When working with webpack and React, developers may encounter issues, especially when setting up custom entry points. One common problem is when webpack fails to find React, leading to errors in the browser console. In this guide, we'll delve into the causes of this issue and provide a step-by-step guide on how to resolve it.

The Problem Explained

Consider a scenario where you've set up a custom entry point in webpack, but you encounter the following error:

[[See Video to Reveal this Text or Code Snippet]]

When you attempt to import React using:

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it works during the build process but fails in the browser. This leads to confusion, especially when attempting to resolve the path by changing it to:

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In this case, webpack throws another error indicating it cannot resolve the module:

[[See Video to Reveal this Text or Code Snippet]]

Why does this happen?

When the script tag in your HTML file points to the actual location of your source script, it bypasses webpack's processing, such as bundling and transformations through Babel. This often leads to errors, as the raw JavaScript file is presented to the browser instead of the compiled output.

The Solution: Fixing the Script Tag

To resolve the issue, you need to ensure the script tag in your HTML file points to the compiled output of webpack, rather than the raw source code. Here's what you need to do:

1. Update Your HTML File

Ensure the <script> tag in your HTML file is correctly referencing the output file generated by webpack:

Incorrect Example:

[[See Video to Reveal this Text or Code Snippet]]

This line points to the source file and not the compiled version that webpack produces.

Correct Example:

[[See Video to Reveal this Text or Code Snippet]]

This line correctly points to the output of the bundling process. In the case of webpack's development server, remember that the file does not physically exist on disk but is served from memory.

2. Double Check Your Webpack Configuration

In your webpack.config.js, verify that the output properties are set correctly:

[[See Video to Reveal this Text or Code Snippet]]

Make sure that filename matches what you are using in the <script> tag of your HTML.

3. Use the Correct Port and Base URL

If you're running webpack-dev-server, ensure you're accessing it at the right URL (typically http://localhost:9000). Adjust your web server if you're using a different port.

Conclusion

By updating the script references in your HTML file and ensuring your webpack configuration is accurate, you can resolve the issue of webpack being unable to find React with custom entry points. Remember that the browser needs the bundled output file to function correctly.

Following these simple steps will not only help you avoid these common pitfalls with webpack and React but also streamline your development process. Happy coding!