Missing language services in TypeScript/JavaScript projects under ASP.NET Core solution

Problem

Sample scenario: There is a "SampleSolution" solution with ASP.NET Core project "SamplePrj". There is a typescript project under "SamplePrj"/vite-project

In .ts file completion for the types from node_modules doesn't work. Symbols that are coming from node_modules are not highlighted.

Sample: Issue can be seen from Solution Explorer. The node_modules folder (ensure Show All Files is enabled) is not indexed. Folders inside are not highlighted properly.

Cause

Angular and/or Vue.js plugins are disabled.

Resolution

Enable Angular and Vue.js plugins from Settings | Plugins. Or Right-click on the problematic TS / JS project folder and select Tools | Attach to Solution: