Why does all the Jasmine related it, describe, beforeEach are marked as "Cannot find name ********"?

I have upgraded Angular app from 14 to 15, Angular Material to 15, and then MDC migration. FYI, rxjs, nodejs, typescript versions mandates have been updated too prior to upgrade.

But in all the spec.ts files, the Jasmine specific keywords like describe, it, beforeEach etc., are all marked with wavy/squiggly line as follows:

And when hovered on the keyword, it is shown as: "Cannot find name 'describe'. Do you need to install type definitions for a test runner? Try npm i --save-dev @types/jest or npm i --save-dev @types/mocha"

In my package.json, I already have "@types/jasmine": "2.8.19", in devDependencies block, and so the respective nodemodules have been generated.

Pleas provide a solution, what could be causing this issue?

• try restarting the code editor/typescript (ctrl+shift+p -> restart ts server in VSCode)
• try deleting node_modules and package-lock.json and do a fresh install