VSCode: Formatter slow or freezes if jsconfig.json is present in project

Describe the bug Since updating to 105.4.0 of the VS Code extension the formatter is really slow or freezes when saving a .svelte file making me having to skip formatting from the VS Code prompt almost every time I’m saving a file. There’s a jsconfig.json present in the project, it’s got a couple of aliases mapped in the root of my project.

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "#js/*": ["./client_src/js/*"],    
      "#api/*": ["./server_src/api/*", "./client_src/js/api/*"],
      "#api/scripts/*": ["./server_src/scripts/api/*"],
      "#api/webapps/*": ["./server_src/webapps/api/*"],
      "#api/restapps/*": ["./server_src/restapps/api/*"],
    }
  },
  "exclude": ["node_modules"]
}

https://code.visualstudio.com/docs/languages/jsconfig

If I remove this file the formatter works as expected.

Version 102.3.0 doesn’t have this problem, I’ve downgraded to that version in the meanwhile.

To Reproduce Add a jsconfig.json file to the project, content doesn’t seem to matter. I added an empty jsconfig.json file, or with an empty object, and this causes the formatter to freeze.

Expected behavior Format the code without freezing.

Screenshots

System (please complete the following information):

• OS: Windows 10
• IDE: VS Code
• Plugin/Package: Svelte for VSCode 102.4.0 102.5.1

[dummdidumm]

Closing as there is nothing we can take action on. If performance problems occur, please open a new issue with a detailed reproduction.

[dummdidumm]

I guess you have set resolveJsonModule to true in your tsconfig.json? That means to TS “import and analyze that file”, which is slow and not avoidable. If you set resolveJsonModule to false instead and provide a d.ts declaration which tells TS to just assume that any file ending with .json is ok like so:

declare module "*.json" {
  const value: any;
  export default value;
}

Then the file is not analyzed and it should be faster. The disadvantage is that you no longer have type definitions for the JSON module and also TS will not error if there’s no JSON file at the path you specify.