How to think in React
Tags: react, javascript, beginners, webdev
Published: 2023-03-05 15:37:31

Thinking in React involves breaking down a user interface into smaller, reusable components and thinking about how the state of these components affects their render. Here's the general process:

## Identify the components
 
Start by identifying the individual components of your UI and what data they will require.

## Determine the state
Determining state in React involves identifying which data is important for the components in your application to function, and where that data should be stored. **Here are some steps to help you determine state:**

**1. Identify the data:** Start by listing all of the data that your components need in order to function.
**2. Decide where to store state:** The state should be stored in the component that will be using it or in the nearest common ancestor of the components that need it.
**3. Evaluate if the data should be state:** Ask yourself if the data needs to change and if so, should it be stored in state or props. If the data will never change, it can be stored as a prop. If it will change, store it in state.
**4. Determine the initial state:** Decide on the initial values for your state, which can be set in the constructor of your component or in a `useState` hook.
**5. Update the state:** Determine when and how the state should be updated, typically through event handlers or form inputs.

It's important to note that the state should only include values that can change in the components, and should be kept to a minimum to ensure efficient updates and re-renders.

## Pass data as props
In React, data is passed from a parent component to its child component(s) as "props". Props are read-only and used to pass data and event handlers down the component tree. **Here's how you can pass data to props in React:**

**1. Define the props in the child component:** Start by defining the props that the child component will receive. This can be done using the props parameter in a class component or by destructuring the props object in a functional component.
**2. Pass the data from the parent component:** In the parent component, pass the data as attributes to the child component. For example:

```
function ChildComponent(props) {
  return <h1>Hello, {props.name}!</h1>;
}

function ParentComponent() {
  return <ChildComponent name="John" />;
}
```
**3. Access the data in the child component:** The child component can access the data passed from the parent component through its props object. For example, in the ChildComponent component, `props.name` will contain the value "John".

It's important to note that props should only be used to pass data from parent to child components, and not for communicating between siblings or across the component tree. In those cases, you should use `state`, `context` or a state management library like `Redux`.

## Think about render
In React, "rendering" refers to the process of converting the component's state and props into HTML elements that can be displayed in the browser. The render method is the most important method in a React component, as it's responsible for rendering the component's view.

Here's an example of a basic render method in a functional component:

```
import React from 'react';

function MyComponent(props) {
  return <h1>Hello, {props.name}!</h1>;
}
```
In this example, the render method is implicitly defined by the return value of the functional component. The render method returns a single React element, which is an object that represents a DOM element.

In class components, the render method is defined explicitly. Here's an example:

```
import React, { Component } from 'react';

class MyComponent extends Component {
  render() {
    return <h1>Hello, {this.props.name}!</h1>;
  }
}
```
In this example, the render method is defined as a method on the MyComponent class. The render method returns a single React element, which is an object that represents a DOM element.

It's important to note that the render method should be a pure function of the component's state and props, and should not have any side effects. This allows React to efficiently update the component's view when its state or props change.

## Break down components 
Breaking down a component in React means dividing a complex component into smaller, more manageable and reusable components. This can help make your code more maintainable and scalable, as well as improve the performance of your application by reducing the number of unnecessary re-renders.

**Here are the steps to break down a component in React:**

**1. Identify the sub-components:** Start by looking at the component and identifying the sub-components or parts of the component that could be extracted into their own components.
**2. Extract the sub-components:** Create a new component for each sub-component and move the relevant code into the new component.
**3. Pass data as props:** Pass data from the parent component to the child components as props, allowing for reusability and a clear data flow.
**4. Test and iterate:** Test the sub-components to ensure they work as expected, and make any necessary adjustments. Repeat the process if necessary, breaking down sub-components further until they are simple and reusable.

It's important to keep in mind that breaking down components should not be taken to an extreme, as too many small components can make your code more complex and harder to maintain. The goal is to find a balance between having simple and reusable components, while also keeping the number of components manageable.

## Repeat 
Repeat the process as needed, making adjustments and improvements as you go along.

Remember, the goal is to have simple, reusable components that effectively manage and display the data they receive.

Thanks for reading! I hope you found this post informative and helpful. If you have any questions or feedback, please feel free to leave a comment below!