[chii]

it's quite likely that your issue is with the actual node_modules directory being referenced as part of your source. It slows the LSP too.

Exclude it (via https://code.visualstudio.com/docs/getstarted/settings) by using

  "files.exclude": {
    "**/.git": true,
    "**/.svn": true,
    "**/.hg": true,
    "**/CVS": true,
    "**/.DS_Store": true,
    "**/Thumbs.db": true,
    "**/node_modules" : true
  }

I've not had any issues with speed ever since i started excluding directories that contain junk stuff that you know you will not ever need to see in a project's view.

[wongarsu]

If you have large files (as in hundreds of MB or bigger) in your project directory, especially text files, it also really pays off to put them into either your .gitignore or the files.exclude.

Often happens to me when I run projects that output large CSVs, and it's a very notable performance impact.