Over the last few weeks, I've been filling in the gaps in my knowledge with React. Although I've built two group projects using this framework, I started from the very beginning to fill in my gaps. Today I will look at React from a more theoretical side rather than just working or building a project.
Today's topic is React "props":
- What are props in React, and how do you pass data from a parent component to a child component using props?
Props(properties) is used for passing data or configurations from a parent component to a child component. Child components can then use these props to render content, make decisions, or perform other tasks based based on the data provided by the parent.
Props are read-only, which means that child components cannot directly modify the data received via props, they are meant for one-way communication from parent to child.
To pass the data using props:
a. Define the parent component - where the data is held to pass to the child
b. Define the Child component - here with props, you can access these props and use them as needed
- Explain the difference between props and state in React?
Props are used for passing data from a parent component to a child component. Props are typically used for configuration and data sharing between components.
State is used for managing and storing component-specific data that can change over time. This is internal data that is owned by the component and acts as the component's "memory". State manages a component's behavior based on user interactions and other events. It can also change over time, triggering re-renders when it does.
- Can you modify the value of props from inside a child component? Why or why not?
No, you cannot modify the value of props from inside a child component in React. Props are designed to be read-only and are meant for one-way communication from parent to child components. Once a parent component passes props to a child component, those props cannot be changed or mutated directly by the child component.
- How would you handle default or missing props in a React component?
Handling default or missing props in React components is essential to ensure that your application doesn't break when expected props are not provided or are undefined. Here are few ways to handle default or missing props:
a. Default Prop Values - using 'defaultProps' property of your component
b. Conditional rendering
c. Prop Validation - achieve this by using 'propTypes' property of your component
d. ES6 Destructuring
e. Error Boundary
- What is prop drilling, and how can you avoid it in your React application?
Prop drilling is where you have to pass props down multiple levels of nested components in order to make the data accessible to a deeply nested child component. This can make the code hard to maintain and understand, as well as making it harder to refactor or modify your component hierarchy.
Instead of using prop drilling, you can use:
a. ContextAPI
b. Redux or other state management libraries
c. Component composition
d. High-Order Components and Render Props
e. React Hooks
This is what Day 22 was all about, learning more of the theory behind the building. These topics are mini-study notes for myself but I would love for them to be helpful for those learning React or preparing for interview questions. Tomorrow we'll chat about React components!