Learn the applications for componentWillUnmount.
- [Instructor] In this video we're going to be talking about…componentWillUnmount.…componentWillUnmount is a great opportunity…for us to tell our component to…basically clean up after itself.…Maybe we have some timers that we want to clear,…or maybe we have some refs…that we want to make sure are emptied.…By strategically using componentWillUnmount,…we can make sure we're putting an end to any processes…that might hurt our apps performance.…So in this video to test this out,…we're going to make a sub-component…that is going to be a child of our parent component…and in it it's going to be doing a polling so,…it's a common way of practice…that you might have an API…that you pull for changes in data.…
And a lot of times that will use something…like setTimeout or setInterval…to periodically go and get information.…Now if you have an interval…that is set up on your application…but you don't put an end to it when the component unmounts,…it might keep running and there could be a scenario…where you have tons and tons and tons of duplicate intervals…
Carl Peaslee helps you build a number of small reusable components that will be useful in future projects. Along the way, he discusses the syntax and uses of lifecycle methods, how state affects React lifecycles and your apps, and how to set static display name, default props, and initial state. Plus, learn how to gather performance data and improve performance by minimizing component updates.
- Overview of React lifecycles
- Initial state
- Default props
- Mounting: componentWillMount, componentDidMount, and render
- Updating: shouldComponentUpdate, componentWillUpdate, and componentDidUpdate
- Controlling component updates
- Using react-addons-perf to get performance data
Skill Level Intermediate
React.js: Building an Interface (2016)with Ray Villalobos1h 21m Intermediate
1. Overview of Lifecycles
2. Defaults, Initialization, and Construction
5. Optimizing Components
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