When does on_mount run? React's componentDidMount() is a lifecycle method that runs after a component mounts, once it's been inserted into the DOM. This is in

When does on_mount run? React's componentDidMount() is a lifecycle method that runs after a component mounts, once it's been inserted into the DOM. This is in contrast to componentWillMount() (now UNSAFE_componentWillMount(), because it breaks when async rendering is enabled), which is called before the component mounts. This naming scheme becomes even more important for the update lifecycle methods-- in addition to componentDidUpdate(), there's a shouldComponentUpdate() called before it (where you can return true/false to tell React whether or not to proceed with the update) and UNSAFE_componentWillUpdate(), called between those two.