Lifecycle of a React App — From Seed to Blossom
Learn the lifecycle of a React app and master the usage of useEffect in functional components for optimal performance. Start building better React applications today!
When building a React app, it’s essential to understand the lifecycle of components. The lifecycle of a React app can be compared to the lifecycle of a plant, where the app goes through various stages from its birth to its eventual removal. In this guide, we’ll explore the different stages of a React app’s lifecycle and learn how to use them in functional components.
Planting the Seed (Initialization)
Just like a plant starts from a seed, a React app begins with the initialization phase. During this phase, React sets up the necessary environment and initializes all the variables required for the app to grow. In class components, this is where the constructor method is called. In functional components, we use the useEffect hook with an empty dependency array to achieve the same behavior.
import React, { useEffect } from 'react';
function MyApp() {
useEffect(() => {
// Code that runs once during initialization
// Perform any one-time setup, such as initializing variables
// Clean up any resources when the component is unmounted
return () => {
// Clean up code
};
}, []);
// Component render and other logic
return <div>My App</div>;
}Sprouting Leaves (Mounting)
Once the seed has been planted, a plant sprouts leaves. In the context of a React app, the mounting phase is where the component structure is created and rendered onto the screen. In class components, the render method is responsible for this stage. In functional components, the rendering is done directly in the function body.
import React from 'react';
function MyApp() {
// Component render
return <div>My App</div>;
}Growing and Blossoming (Updating)
As a plant grows, it adapts to changing conditions. Similarly, a React app updates itself to reflect new data and changes in state. In class components, the componentDidUpdate method is responsible for handling these updates. In functional components, we use the useEffect hook with specific dependencies to achieve the same behavior.
import React, { useEffect, useState } from 'react';
function MyComponent({ value }) {
const [data, setData] = useState('');
useEffect(() => {
// Code that runs whenever 'value' or 'data' changes
// Perform actions based on the updated 'value' or 'data'
// Clean up any resources when the component is unmounted
return () => {
// Clean up code
};
}, [value, data]); // Specify 'value' and 'data' as dependencies
// Component render and other logic
return <div>My Component</div>;
}Pruning and Trimming (Unmounting)
Just as we prune and remove unnecessary parts of a plant, we may need to remove components or stop rendering them in a React app. The unmounting phase is where a component is cleaned up and removed. In class components, the componentWillUnmount method handles this stage. In functional components, we return a cleanup function from the useEffect hook to achieve the same behavior.
import React, { useEffect } from 'react';
function MyComponent() {
useEffect(() => {
// Code that runs once when the component is mounted
// Perform any one-time setup
// Clean up any resources when the component is unmounted
return () => {
// Clean up code
};
}, []);
// Component render and other logic
return <div>My Component</div>;
}Understanding these lifecycle stages and how to use them in React functional components is crucial for building robust and interactive applications. By leveraging the useEffect hook, we can handle side effects and manage the lifecycle of our components effectively. Remember, just like plants, React apps can grow, change, and adapt, making them powerful tools for creating dynamic user interfaces.
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In conclusion, the lifecycle of a React app can be compared to the growth stages of a plant. By grasping these stages and utilizing the appropriate lifecycle methods in functional components, you’ll be well-equipped to develop React applications with optimal performance and functionality.
Hope the above article gave a better understanding. If you have any questions regarding the areas I have discussed in this article, or areas of improvement don’t hesitate to comment below.
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[Disclosure: This article is a collaborative creation blending my own ideation with the assistance of ChatGPT for optimal articulation.]
