JS-201-ReactFundamentals
  • Part 0: App Overview
  • Part 1: Intro to React
    • 1.0: Packages Setup
    • 1.1: Project Setup
    • 1.2: React Router Dom
  • Part 2: JavaScript Concepts
    • 2.0: ES6 Overview
    • 2.1: classes
    • 2.2: constructors
    • 2.3: extends
    • 2.4: super
    • 2.5: interpolation
    • 2.6: map
    • 2.7: filter
  • Part 3: Functional Components
    • 3.0: Functional Components Overview
    • 3.1: Calling Functional Components
    • 3.2: Single Element Rule
    • 3.3: Arrow Functions
    • 3.4: Challenge
    • 3.4: Solution
    • 3.5: Challenge 2
    • 3.5: Solution 2
  • Part 4: JSX Challenge
    • 4.1: JSX Overview
    • 4.1: Challenge Answer
    • 4.2: className
  • Part 5: Class Concepts
    • 5.1: State
    • 5.2: setState
    • 5.3: Class Components Challenge
    • 5.4: Class Components Challenge Answer
  • Part 6: Props Starter
    • 6.0: Props Overview
    • 6.1: Props Demo and Challenge 1
    • 6.2: Props Answer 2
    • 6.3: Props Passing Functions and Challenge 2
    • 6.4: Props Answer 2
    • 6.5: External Props and Mapping Components
    • 6.6: PropTypes
  • Part 7: Lifecycle Methods
    • 7.0: Lifecycle Overview
    • 7.1: Lifecycle Methods
    • 7.2: Mounting Methods
    • 7.3: Update Methods
    • 7.4: Unmount Methods
  • Part 8: Apps
    • 1.0 - Small Timer Apps
      • 1.1 - Simple Timer
      • 1.2 - Clock App
      • 1.3 - Stop Watch App
      • 1.4 - Challenge
    • 2.0 - Concept List
      • 2.1 - Concept Data
      • 2.2 - Concept App Component
      • 2.3 - Concept Component
      • 2.4 - Concept List Component
    • 3.0 - NYT
      • 3.1 - NytApp Component
      • 3.2 - Nyt Results
    • 4.0 - The Friend List App
      • 4.1 - Friend List App Component
      • 4.2 - Friend Component
    • 5.0 - Movie Search Application
      • 5.1 - Form Component
      • 5.2 - Form Results Component
      • 5.3 - Styled Components
    • 6.0 - YouTube Api
      • 6.1 - Video Component
      • 6.2 - Video Component
      • 6.3 - Video Component
    • 7.0 - Github Api Application
      • 7.1 - The Users
      • 7.2 - Github API Component
      • 7.3 - Github API Card
      • 7.4 - Github API Card Form
      • 7.5 - Github API Card List
      • 7.6 - Github API Search
      • 7.7 - Github API Challenge
    • 8.0 - Bitcoin Api Application
      • 8.1 - Bitcoin API Setup
      • 8.2 - Bitcoin API Fetch
      • 8.3 - Bitcoin API Line Chart
      • 8.4 - Bitcoin API Fetching Data
      • 8.5 - Bitcoin API Info Box
      • 8.6 - Bitcoin API Completed Code
    • 9.0 - Google Maps Api Challenge
    • 10.0 - Sound Cloud App Challenge
    • 11.0 - VR App Challenge
    • 12.0 - React Native Intro
  • Part 9: Project
  • Part 10: Notes
    • 10.1 - Resources
    • 10.2 - Troubleshooting
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  • Unmount Phase Method
  • componentWillUnmount() *
  1. Part 7: Lifecycle Methods

7.4: Unmount Methods

Unmount Phase Method

componentWillUnmount() *

componentWillUnmount() is called right before a component is unmounted and destroyed. Perform any necessary cleanup in this method, such as invalidating timers, canceling network requests, or cleaning up any subscriptions that were created in componentDidMount(). If we don't take the time to remove events we can create memory leaks in our system which will slow down your application and make performance terrible. React will often do a good job of telling you that you're trying to update something that is no longer mounted if you forget to do this, so if you see this message make sure you've cleaned up everything in componentWillUnmount() for your components.

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Last updated 7 years ago