Debugging Parcel Projects: Common Issues Quiz Quiz

Assess your ability to identify and resolve frequent troubleshooting scenarios in parcel-based development workflows. Hone your skills with parcel bundler errors, configuration pitfalls, and environment handling through real-world debugging questions.

1. Entry File Not Found Error

   When attempting to run a parcel build, the terminal displays 'Cannot find the entry file index.htm', even though your main HTML file is inside the src folder as index.html. What is the most likely cause of this error?

   1. Parcel does not support HTML files as entry points.
   2. There is a syntax error inside your index.html.
   3. You provided an incorrect entry file path in your build command.
   4. The output directory is missing.

   Explanation: If your actual main file is located in 'src/index.html' but you specify 'index.htm' or omit the folder path, parcel cannot locate it, leading to an entry file not found error. Parcel does support HTML entry points, so option two is incorrect. A syntax error inside the HTML would typically generate a different error message after the file is located. Missing output directories do not trigger errors during entry file resolution; bundle tools usually create them if needed.

2. Module Not Found during Import

   Your project throws a 'Module not found' message when you import a JavaScript file as './utlis.js' even though the file exists. What is the most probable reason for this error?

   1. You need to restart your terminal.
   2. The import path contains a typo in the filename.
   3. Parcel does not recognize JavaScript files.
   4. Your project is missing a configuration file.

   Explanation: A typo such as './utlis.js' instead of './utils.js' will prevent parcel from locating the intended file, resulting in a module not found error. Parcel fully supports JavaScript files, so the second option is not applicable. While missing configuration files may cause other issues, they typically do not lead to this error. Restarting the terminal does not solve import path problems caused by typos in filenames.

3. Caching Causing Outdated Output

   After fixing a bug in your code, the parcel output still shows the old error in the browser until you clear the cache. What issue is likely causing this behavior?

   1. A dependency is missing from your project.
   2. An invalid CSS property is used.
   3. The code editor did not save your files before running.
   4. Parcel is serving cached files from a previous build.

   Explanation: Parcel uses caching to speed up builds and may sometimes serve outdated files if the cache does not update properly, which explains why browser output lags behind code changes. Unsaved files would prevent any changes from occurring and are usually more obvious issues. Missing dependencies typically stop the build instead of showing outdated output. Invalid CSS properties are unrelated to the JavaScript or HTML error described here.

4. Environment Variable Not Found

   In your parcel project, a process.env variable is undefined at runtime even though it is specified in your .env file. Which mistake most often causes this problem?

   1. You are using the wrong output file extension.
   2. Your entry script does not import any modules.
   3. The .env file is placed in the wrong directory.
   4. The output directory is not specified.

   Explanation: Placing the .env file outside the project's root directory prevents environment variables from being loaded, resulting in undefined values at runtime. Output file extensions and missing output directory are not related to environment variable resolution. Entry scripts not importing modules do not directly impact environment variables being loaded from the .env file.

5. Unexpected Token Error in Stylesheet

   A build fails with an 'Unexpected token' message pointing to your main.css file after you add a new syntax. What is the most probable reason for this error?

   1. Your HTML file refers to the wrong stylesheet path.
   2. You used a CSS feature not supported by your current project setup.
   3. A JavaScript variable is not properly declared.
   4. A dependency was installed into the wrong folder.

   Explanation: Introducing modern or experimental CSS features without configuring appropriate support in your build setup often leads to parsing errors like 'Unexpected token'. Linking to an incorrect stylesheet would typically generate a 'not found' error rather than a token error. JavaScript variable declaration issues would not directly cause CSS parse errors. Installing dependencies in the wrong folder does not usually affect CSS parsing errors.