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Introduction
Props and state are two fundamental concepts in React. Props are used to pass data from a parent component to a child component, while state is used to manage data within a component.
Props
Props are immutable, meaning they cannot be changed by the child component. They are passed down from the parent component and are read-only within the child component.
State
State is mutable, meaning it can be changed by the component. State is managed within the component and is not accessible to other components.
Differences
| Characteristic | Props | state |
|---|---|---|
| Ownership | Owned by the parent component | Owned by the component itself |
| Mutability | Immutable | Mutable |
| Scope | Passed Down From The Parent Component | Only accessible within the component where it is defined |
When to use props
- To pass data from a parent component to a child component.
- To represent data that is constant or does not change over time.
- To simplify the component hierarchy.
When to use state
- To manage data that changes over time.
- To represent data that is specific to the component.
- To create interactive components.
Identifying props and state
To identify whether something falls into props or state, use the following rule of thumb:
- If a component needs to alter one of its attributes at some point in time, that attribute should be part of its state.
- Otherwise it should just be a prop for that component.
Stateless VS. Stateful components
Components can be stateless or stateful:
- Stateless components have only props and no state.
- Stateful components have both props and state.
Stateless components are simpler and easier to test than stateful components. However, stateful components are needed to create interactive components.
Conclusion
Props and state are two important concepts in React. By understanding the differences between props and state, you can build more efficient and reusable components.
Additional notes
- Props and states are both plain JavaScript objects.
- Props and states are deterministic, meaning that the component always generates the same output for the same combination of props and state.
- Changes to props and states both trigger a render update.
- Stateless components are generally preferred over stateful components.
- Components can be differentiated into types based on props and state. For example, components can be stateless or stateful.
I hope this annotation is helpful. Please let me know if you have any questions.