PERF_ISSUE.md

Performance Issue Reporting

Performance issues are hard to track down, and a good report is crucial for fixing them.

Although you can use the command Vetur: Restart VLS (Vue Language Server) to restart VLS and temporarily avoid performance issues, we would appreciate it if you can file a report to help us fix the issue.

In addition to the normal issues, please include a profile in performance-related issues and below information:

• TypeScript version (Find it in Output -> Vue Language Server)

Profiling

Vetur has 2 parts:

• The client at /client. This is a normal VS Code extension.
• The server (Vue Language Server) at /server. This is a language server.

Here is a rough illustration:

The perf issue is mostly caused by the server. Here's how to profile it.

• You need Chrome for profiling.
• Set vetur.dev.vlsPort to a number, say 8000.
• Open chrome://inspect/ in Chrome.
• You should see a Node.js remote target like below. That's the VLS process. Click it.
  • If you don't see the target, click Open dedicated DevTools for Node and in the Connection tab, click Add connection and add localhost:<vetur.dev.vlsPort>
• Go to the Profiler tab. Click Start.
• Edit some Vue files in your editor.
• Click Stop.
• Save the profile. Zip it and attach to issue report.