Mastering TypeScript with React: A Comprehensive Guide
The Challenge of Dynamic Typing in JavaScript
JavaScript’s dynamic typing can lead to confusion and errors in your codebase. Variables can be anything, making it difficult to maintain large-scale applications. To address this issue, Microsoft introduced TypeScript, a static-typed version of JavaScript.
The Power of TypeScript
TypeScript enables developers to statically type data and variables, making it an ideal choice for large-scale application development. Its lead architect, Anders Hejlsberg, envisioned a system that strengthens JavaScript with features like static typing, classes, and modules.
TypeScript and React: A Perfect Pair
TypeScript has become the go-to choice for React developers, allowing them to write their React apps with confidence. However, typing React components, props, and state can be challenging. This guide aims to provide a quick reference and learning resource for both beginner and advanced React developers.
Understanding TypeScript Typings
TypeScript uses a typings folder to store files with a .d.ts extension. These files contain interfaces that infer the shape of a value, enabling TypeScript to bring data typing to JavaScript. An interface describes what a value would look like, making it easier to define the shape of your data.
Function Components
Function components are normal functions that return JSX elements in React. They can be made stateful and smart with the help of React hooks. Defining a React function component takes the React.FunctionComponent shape, which can be shortened to React.FC. You can type props definitions using the AppProps interface.
Class Components
Class components are used to create views in React and define how a small unit of the UI should appear. They have lifecycle hooks that allow you to run custom code at any state of the component’s lifecycle. Class components use the React.Component<> shape, and you can provide props and state type parameters.
Forms and Events
Forms are used to collect information in an internal state. React uses the React.FormEvent type to generally type events from elements. You can omit typing the handler’s argument with React.FormEvent and type the return value of the handlers instead.
Hooks
Hooks are supported in React v16.8+ and allow you to use state in functional components. useState is used to set state in functional components, and the state is kept alive throughout the lifetime of the component. You can infer state to be a number and setState a function that takes numbers.
useReducer
useReducer allows you to maintain state and concurrently dispatch actions to the store from your functional components. It takes an initial state and a reducer function, and you can define a type of the state and type the reducer function based on the return type.
useRef
useRef allows you to access refs in React nodes and maintain them throughout the lifetime of the component. You can be more specific in the type of element you are trying to reference.
useContext
useContext allows you to create and maintain contexts in your functional components throughout their lifetime. The contexts are created using the React Context API, and you can use useContext and createContext to create a context.
Take Your Development to the Next Level
By mastering TypeScript with React, you can take your development skills to the next level. With this guide, you’ll be able to quickly look up best practices and generic TS types in React. Start building more maintainable and efficient applications today!