10 React TypeScript Best Practices

React is a popular JavaScript library for building user interfaces. TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. In this article, we’ll look at 10 best practices for working with React and TypeScript.

1. Use TypeScript

TypeScript is a typed superset of JavaScript that compiles to plain JavaScript. It adds an extra layer of safety and quality assurance to your codebase by catching errors early and making it easier to refactor code.

React is a JavaScript library for building user interfaces. While you can use React without TypeScript, using TypeScript with React will give you the benefits of both technologies.

Some of the benefits of using TypeScript with React include:

– Better code quality
– Early error detection
– Easier code refactoring
– Improved developer experience

2. Use React Hooks

React Hooks are a way to use state and other React features without writing a class. They’re also more type-safe than traditional React code, which is important when using TypeScript.

There are many different React Hooks, but some of the most popular ones are useState, useEffect, and useRef.

useState allows you to use state in functional components, which is not possible with traditional React code.

useEffect lets you perform side effects in functional components, which is again not possible with traditional React code.

useRef lets you create mutable variables in functional components, which can be useful for creating things like text input fields.

3. Avoid using any

Any is a type that represents any value. It’s a top type, which means it can be assigned to any other type. However, using any should be avoided because it defeats the purpose of using TypeScript, which is to catch errors early.

If you use any, TypeScript will not be able to check for correct types, and you will end up with errors that could have been caught earlier. So, avoid using any and make sure all your types are well-defined.

4. Use defaultProps and propTypes together

If you’re using TypeScript with React, you should always use defaultProps and propTypes together. The reason is that defaultProps provides a way to specify the type of a prop, but it only does so if the prop is not provided. However, if the prop is provided, then TypeScript will infer the type from the value that is provided.

This means that if you only use defaultProps, then TypeScript will only know the types of props that are not provided. On the other hand, if you only use propTypes, then TypeScript will only know the types of props that are provided. But if you use both defaultProps and propTypes, then TypeScript will know the types of all props, whether they are provided or not.

So using both defaultProps and propTypes together is the best way to ensure that TypeScript knows the types of all props in your React component.

5. Prefer class components over function components

Class components are more powerful than function components, as they give you access to additional features like state and lifecycle hooks. With TypeScript, class components also offer better type safety.

Function components are simpler and easier to write, but they don’t offer the same level of power and flexibility as class components. If you’re just getting started with React and TypeScript, you may want to start with function components, but you should eventually migrate to class components.

6. Use the useEffect hook to manage side effects

The useEffect hook is a React function that takes a function as an argument and returns a cleanup function. The function passed to useEffect will run after the component renders, but before the component unmounts. This makes it ideal for managing side effects, such as fetching data from an API or subscribing to a event listener.

If you’re not familiar with React hooks, don’t worry. They’re just functions that let you use React features in functional components. You can read more about them in the React documentation.

So, why is using the useEffect hook a best practice? Well, because it helps keep your code clean and organized. All of your side effect logic will be contained in one place, making it easier to debug and test. Additionally, if you ever need to unsubscribe from an event listener or cancel a network request, you can do so within the useEffect cleanup function.

7. Don’t forget about the children prop

The children prop is used to pass elements to a component, and it’s one of the ways you can make your components more flexible. If you have a component that only renders a single element, you can use the children prop to pass that element to the component.

For example, let’s say you have a Button component that only renders a button element. You can use the children prop to pass the text for the button:

import React from ‘react’;

function Button({ children }) {
return (
{children}
);
}

export default Button;

This way, you can reuse the Button component and only have to worry about passing the text for the button. You don’t have to worry about the button element itself.

Of course, you can also use the children prop to pass multiple elements to a component. For example, you could use the children prop to pass a list of items to a List component:

import React from ‘react’;

function List({ children }) {
return (

{children}

export default List;

Again, this makes your components more flexible and easier to reuse.

8. Use a linter

A linter is a tool that helps you find and fix errors in your code. It can be used to enforce coding conventions, such as those defined in the official React style guide.

Using a linter can help you avoid common mistakes, such as forgetting to add a type annotation to a variable. It can also help you spot potential problems, such as using an incorrect type for a prop.

There are many different linters available, but we recommend using ESLint with the React TypeScript plugin. This plugin will automatically detect errors in your code and suggest fixes.

9. Use static type checking for props in function components

When you use TypeScript with React, you can define the types of props that a component expects to receive. This is important for two reasons.

First, it ensures that the correct type of props is being passed to the component. For example, if a component expects to receive a string as a prop, but an integer is passed instead, TypeScript will give you an error.

Second, it allows you to document the types of props that a component expects to receive. This documentation can be extremely helpful for other developers who are working on your code.

To static type check props in a function component, you first need to define the types of props that the component expects to receive. This is done using the interface keyword.

For example, let’s say we have a component that expects to receive a name and an age as props. We could define the interface for this component like this:

interface Props {
name: string;
age: number;
}

Once the interface has been defined, we can then use it to type check the props in our component:

function MyComponent(props: Props) {
// …
}

MyComponent.propTypes = {
name: PropTypes.string,
age: PropTypes.number
};

As you can see, we use the interface to type check the props argument in our component function, and we also use the PropTypes library to validate the props when the component is used in production.

Using static type checking for props in function components is a best practice because it helps to ensure that the correct type of props is being passed to the component, and it also provides valuable documentation for other developers who are working on your code.

10. Use the key prop when rendering lists of elements

When you render a list of elements in React, each element is given a key attribute. The value of the key attribute should be unique among all the other keys in the list, and it helps React identify which items have changed, been added, or been removed.

If you don’t use the key prop when rendering lists of elements, React will automatically generate a key for each element, based on its position in the array. This can cause problems if the order of the elements changes, because React will think that all the elements have been removed and re-added in the new order.

Using the key prop ensures that React will always correctly update the list of elements, even if their order changes.