--- title: "The Secret Of Controlling Component Instances In React" url: https://daily.dev/posts/the-secret-of-controlling-component-instances-in-react-py9qhgphl source_url: https://towardsdev.com/the-secret-of-controlling-component-instances-in-react-abdf87854079?source=rss----a648dc4ecb66---4 type: article source: "Towards Dev" published: 2022-09-07T13:49:36.122Z updated: 2022-09-07T13:49:36.121Z tags: ["react", "javascript", "angular"] reading_time: 2 upvotes: 13 comments: 0 language: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # The Secret Of Controlling Component Instances In React **[Towards Dev](https://daily.dev/sources/towardsdev)** · 2 min read · 13 upvotes · 0 comments ## Summary The key prop is used by React to identify which items have changed, are added, or are removed. Unmounting the previous instance simply means that all state that had existed in the component is completely removed. This is another little known secret about React key prop. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [Don’t just attend KubeCon \+ CloudNativeCon, Merge Forward your experience\!](https://daily.dev/posts/don-t-just-attend-kubecon-cloudnativecon-merge-forward-your-experience--l0rpp73x8) · CNCF · 0 upvotes · 0 comments - [Announcing H2 2026 KCDs](https://daily.dev/posts/announcing-h2-2026-kcds-m96goajm1) · CNCF · 1 upvotes · 0 comments - [Two months of Open Community Groups](https://daily.dev/posts/two-months-of-open-community-groups-asf52zhbs) · CNCF · 0 upvotes · 0 comments - [CNCF Unveils Schedule for KubeCon \+ CloudNativeCon Europe 2026](https://daily.dev/posts/cncf-unveils-schedule-for-kubecon-cloudnativecon-europe-2026-ikhcoa5cb) · CNCF · 2 upvotes · 0 comments - [CNCF Debuts KubeCon \+ CloudNativeCon Japan 2026 Schedule](https://daily.dev/posts/cncf-debuts-kubecon-cloudnativecon-japan-2026-schedule-xp5pyudub) · CNCF · 1 upvotes · 0 comments --- Tags: [#react](https://daily.dev/tags/react), [#javascript](https://daily.dev/tags/javascript), [#angular](https://daily.dev/tags/angular) [View this post on daily.dev](https://daily.dev/posts/the-secret-of-controlling-component-instances-in-react-py9qhgphl)