What does `useState` do and when should you use it?

Summary

useState stores local component state and provides a setter that schedules re-rendering when the value changes.

Longer Answer

Use it for simple local UI state such as form fields, toggles, selected tabs, open/closed state, and small client-side values. The setter can take a value or an updater function that receives previous state.

Use functional updates when the next value depends on the previous value. Avoid storing values that can be derived from props/state during render, and avoid using state for mutable values that do not affect rendering.

Key Points

• Use it for simple local UI state such as form fields, toggles, selected tabs, open/closed state, and small client-side values
• The setter can take a value or an updater function that receives previous state
• Use functional updates when the next value depends on the previous value
• For 'What does useState do and when should you use it?', 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 functional updates when the next value depends on the previous value. Avoid storing values that can be derived from props/state during render, and avoid using state for mutable values that do not affect rendering

Comparison / Tradeoffs

Use functional updates when the next value depends on the previous value. Avoid storing values that can be derived from props/state during render, and avoid using state for mutable values that do not affect rendering. |

Summary

useState stores local component state and provides a setter that schedules re-rendering when the value changes.

Longer Answer

For 'What does useState do and when should you use it?', 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 functional updates when the next value depends on the previous value. Avoid storing values that can be derived from props/state during render, and avoid using state for mutable values that do not affect rendering.

Key Points

• For 'What does useState do and when should you use it?', 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 functional updates when the next value depends on the previous value
• Avoid storing values that can be derived from props/state during render, and avoid using state for mutable values that do not affect rendering
• Use the answer to connect the concept back to a realistic production or interview scenario for 'What does useState do and when should you use it?'

Comparison / Tradeoffs