Warning: Your Code’s Best Friend Might Be a CPU Thief!

Visual Studio Code (VSCode) has become a go-to editor for developers due to its flexibility, vast extension library, and active community. One of the extensions that aimed to enhance developers' productivity is the Import Cost (also known as wix.vscode-import-cost) extension. But what happens when an extension designed to help you starts to hurt your coding experience instead? In this post, we’ll explore what the Import Cost extension is, why developers use it, the performance issues it has caused, and what you can do if you’re affected.

What is the Import Cost Extension?

The Import Cost extension provides developers with valuable insights into their code by displaying the size of imported JavaScript modules directly in the editor. By knowing the size of these modules, developers can make informed decisions about their imports, potentially optimizing application performance and reducing load times. This functionality is especially useful in larger applications where module size can significantly impact performance and resource usage.

Why Do Developers Use It?

1. Optimized Bundle Size: The extension helps developers keep track of the size of their imports, encouraging them to choose lighter alternatives where possible.
2. Improved Performance: By monitoring the size of dependencies, developers can reduce unnecessary bloat, ultimately improving application load times.
3. Immediate Feedback: Displaying module sizes right in the code editor provides immediate feedback, allowing for quick adjustments and better coding practices.

With such benefits, it’s no wonder that many developers have turned to this extension to help manage their projects.

The Problems with the Import Cost Extension

Despite its initial promise, many users have reported significant issues with the Import Cost extension. Here’s a closer look at the problems:

High CPU Usage and Performance Issues

A recurring theme in user feedback is the extension's tendency to cause high CPU usage. Developers have noted that the extension leads to frequent CPU spikes, which can slow down not just VSCode but the entire system. This behavior has been frustrating, especially for those who rely on their IDE for efficient workflow.

Here are a few examples:

• vscode keeps crashing when i open a particular file. according to the bisect report this particular extension called import Cost is the one causing the problem.
• just work on vue/scss files running on npm run dev, then it starts to max out all cups and ram usually for several minutes, then stops, but starts again if i continue to edit files. it eventually crashes vscode.
• Frequent CPU spikes to 80%+ with this extension
• Takes too Long to Save File
• Keeps crashing vscode extensions

Unfortunately, despite many users sharing similar issues in the GitHub Issues tab, none of these reports have received any official response in over two years. The lack of updates or community support leaves these performance issues unresolved, raising concerns about whether the extension will see any future improvements.

Impact on Development Experience

The performance issues stemming from the extension have several implications:

1. Slower Code Suggestions: The high CPU usage can lead to lag in IntelliSense and code suggestions, disrupting the coding flow.
2. Increased Fan Noise and Heat: Many users have reported that their PC fans run at high speeds due to the CPU strain, leading to uncomfortable working conditions and higher temperatures.
3. Overall System Slowdown: The performance issues extend beyond VSCode, affecting other applications and leading to a less efficient workflow.

Even If It's Not Harmful Now, Consider the Risks

Even if the Import Cost extension isn’t currently causing problems on your PC, it’s worth noting that the last update was in 2022. The lack of responsiveness from the maintainers regarding reported issues raises concerns about the extension's longevity and reliability. Without regular updates and bug fixes, there's a risk that existing problems may worsen over time, or new compatibility issues may arise with future versions of VSCode. This uncertainty can jeopardize your productivity and overall development experience.

Testing for Problematic Extensions Like Import Cost

If you suspect that an extension like Import Cost is affecting your system’s performance, here are some steps to test it under controlled conditions:

• Set Up a Simple Workspace: Create a minimal project or workspace with just a few files in your main language, without any heavy frameworks. This setup reduces variables and makes it easier to detect if performance issues are directly tied to an extension.
• Use CPU and Temperature Monitoring as Secondary Indicators: While CPU usage and temperature alone might not provide conclusive evidence, you can still monitor these metrics for unusual spikes during light workloads in your simplified workspace.
• Track System Responsiveness with and without Extensions: In your controlled workspace, try using VSCode with Import Cost (or another suspected extension) enabled, then compare by disabling it. Pay attention to things like typing lag, code suggestions, and file save speeds. If these improve significantly when the extension is disabled, it’s likely having an impact.

Utilizing Extension Bisect for Precise Troubleshooting

VSCode’s Extension Bisect feature is particularly useful in identifying extensions that strain resources even in larger or more complex projects:

• Efficient Diagnosis: Extension Bisect automates the process of enabling and disabling extensions in a controlled way, allowing you to pinpoint the source of issues with minimal manual work.
• Quick and Reliable Results: By narrowing down extensions one by one, you can quickly confirm if a particular extension, like Import Cost, is responsible for slowdowns or other performance issues, regardless of your project setup.

How to Use Extension Bisect

1. Open Extension Bisect:

• In VSCode, press Ctrl+Shift+P (or Cmd+Shift+P on Mac) to open the Command Palette.
• Type Extension Bisect and select Start Extension Bisect from the dropdown.

2. Follow the Bisect Process:

• VSCode will begin enabling and disabling extensions in batches. After each batch, you'll be prompted to answer whether the issue still persists.
• If the problem continues, select I can reproduce. If the issue is resolved, select I can't reproduce
• The process will continue narrowing down extensions until it isolates the one causing the issue.

3. Finish and Review Results:

• Once Extension Bisect identifies the problematic extension, VSCode will notify you.
• You can choose to Disable, Uninstall, or Investigate the extension further (e.g., checking its GitHub page for open issues).