React performance: React.memo?

Summary

React.memo memoizes a component render result so React can skip re-rendering when props are equal.

Longer Answer

By default it does a shallow comparison of props. It helps when a component is expensive to render and receives stable props, especially inside large lists or trees. It does not prevent renders caused by the component's own state or context changes.

Use React.memo after profiling or when the cost model is obvious. It can be defeated by passing new object/function props every render, and custom comparison functions can become slower or incorrect.

Key Points

• By default it does a shallow comparison of props
• It helps when a component is expensive to render and receives stable props, especially inside large lists or trees
• It does not prevent renders caused by the component's own state or context changes
• For 'React performance: React.memo?', the key is to explain what problem the concept solves, where it fits in React's rendering model, and what mistake causes production bugs.

Use React.memo after profiling or when the cost model is obvious. It can be defeated by passing new object/function props every render, and custom comparison functions can become slower or incorrect

Comparison / Tradeoffs

Use React.memo after profiling or when the cost model is obvious. It can be defeated by passing new object/function props every render, and custom comparison functions can become slower or incorrect. |

Summary

React.memo memoizes a component render result so React can skip re-rendering when props are equal.

Longer Answer

For 'React performance: React.memo?', the key is to explain what problem the concept solves, where it fits in React's rendering model, and what mistake causes production bugs.

Use React.memo after profiling or when the cost model is obvious. It can be defeated by passing new object/function props every render, and custom comparison functions can become slower or incorrect.

Key Points

• For 'React performance: React.memo?', the key is to explain what problem the concept solves, where it fits in React's rendering model, and what mistake causes production bugs
• Use React.memo after profiling or when the cost model is obvious
• It can be defeated by passing new object/function props every render, and custom comparison functions can become slower or incorrect
• Use the answer to connect the concept back to a realistic production or interview scenario for 'React performance: React.memo?'

Comparison / Tradeoffs