You'll learn to use TypeScript and Twilio Programmable Video to build a video chatting application with muting and unmuting controls. You'll use an existing base project making use of the Twilio Client Library (for front-end video) and the Twilio Server Library (for back-end authentication). The application will have buttons for muting and unmuting audio and video tracks, and will display a notification when another user mutes or unmutes their stream. You'll also manage track attachment and subscription for remote participants, and handle mute and unmute events for tracks this participant has already published. You can run the application by starting your local backend server and client's server, then visit localhost:1234 in your browser to see a preview of your webcam stream after providing the relevant permissions if prompted. By opening two browser windows, you can connect both to the same room but with different identities, and you should see the remote streams. To test the new feature, run the application by starting your local backend server and client's server, then visit localhost:1234 in your browser to interact with the video chatting application.