Why useEffect Running Twice and How to Handle It Well in React

Understanding useEffect Double Invocation in React

React's Strict Mode can cause useEffect to run twice during development, which often catches developers off guard. This behavior is intentional, helping developers identify potential issues in their component lifecycle and side effects.

Why Does useEffect Run Twice?

In development mode, React intentionally double-invokes certain lifecycle methods to:

• Detect unexpected side effects
• Ensure component predictability
• Help developers write more robust code

Strategies to Handle Double Execution

To manage useEffect's double invocation, developers can implement several proven techniques:

• Use useRef to track component mount state
• Implement proper cleanup functions
• Utilize AbortController for API requests

Practical Solutions

The video tutorial provides in-depth explanations and code examples demonstrating how to effectively manage useEffect challenges. From preventing duplicate API calls to implementing robust cleanup mechanisms, you'll learn practical techniques to optimize your React components.

Watch the full video tutorial here: React useEffect Double Execution Explained

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Key Takeaways

• Understand React Strict Mode's purpose
• Learn techniques to handle useEffect double invocation
• Implement efficient side effect management