Building your own Hooks lets you extract component logic into reusable functions. When we want to share logic between two JavaScript functions, we extract it to a third function. Both components and Hooks are functions, so this works for them too!

A custom Hook is a JavaScript function whose name starts with ”use” and that may call other Hooks.

Sources:

Building Your Own Hooks –. (n.d.). React. reactjs.org/docs/hooks-custom.html