As you mentioned this is for an Angular app, just to make things clear, you should NOT use the client credentials flow in the front end. It is ONLY for use side-server as it requires credentials that should never be exposed to the frontend user.
If you intend to make API requests client-side (such as in the Angular app) use the Implicit auth flow https://dev.twitch.tv/docs/authentication/getting-tokens-oauth#oauth-implicit-code-flow where you send the user to Twitch, they accept your app, and are redirected back to your site with a token.