In this video, the author demonstrates how to use React and TypeScript to create a simple user interface. They test a failing test and then add a url parameter to the test, which passes. Next, they add a hello() function to the test and check that it works. In the second part of the video, the author demonstrates how to use React and TypeScript to create a simple web application. He first shows how to create a simple React component, and then how to use TypeScript to declare the types of the component's parameters and state. He then demonstrates how to use React and TypeScript to create a fallback component that handles cases where the main component fails. Finally, he shows how to use React and TypeScript to create a user interface that displays the fallback component and the user's avatar.
In this video, the presenter demonstrates how to use React and TypeScript to build a simple web application. They discuss how to import React, use avatar URLs, and fetch resources. They then run into an error and discover that fetch is not defined in a browser context. They investigate and find that the error is caused by the fact that they are running the tests in a node environment instead of in a browser. They conclude that it may just be fetch that is missing from the code and that they should try to find a way to mock it.