vs code how to know wich jscript formatter code example

Example 1: vs code jsconfig

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "ClientApp/*": ["./ClientApp/*"]
    }
  }
}

Example 2: type checking js vscode

//type checking all js files (vscode)  

//in settings.json:
 "javascript.implicitProjectConfig.checkJs": true

//also gives you ability to enable TypeScript features like auto-import on save