This web part is intended to be easier to understand for new developers building their first SPFx web part. It is a refactoring of the HelloWorld web part that is created by the @microsoft/generator-sharepoint Yeoman generator, and introduces React Functional Components.
Open this sample in the gallery (popup panel): Open in gallery
Source: https://github.com/pnp/sp-dev-fx-webparts/tree/main/samples/react-functional-component