Run npm install or yarn install to install packages
Open src/index.ts in lsp-compatible editor
If plugins are working you should see following errors:
Line 4: Type 'string' is not assignable to type 'number'.
Line 8: Property 'class2' does not exist on type '{ class: string; someOtherClass: string; }'. Did you mean 'class'?
If they are not working the erorr is:
Line 2: Cannot find module './component.svelte' or its corresponding type declarations.