Data Fetching

Part of the React course

Almost no real app can get by showing only data the user already has on their screen. At some point a component needs to ask a server for something, a list of users, a product's details, a page of search results, and until that answer comes back there is a gap of time where the component has nothing to show yet, and a real chance the answer never comes back at all because the network failed.

Calling a server is a side effect, something that reaches outside of "compute this component's JSX from its current props and state," in the same family as starting a timer or opening a connection. If you called fetch directly in a component's body, it would fire on every single render, including renders that happened for reasons that have nothing to do with needing fresh data, and each of those calls would...