useEffect react hook

Using this hook tells React that it needs to do something after render. By default it runs after the first render and after every update.

Dependency array cheatsheet:

1. By default if no array is provided it is executed on mount and every render.
2. [foo] the effect will be called on first render and every time foo changes.
3. [] an empty dependency array will result in the effect function called only on mount.

Source