React & Redux in TypeScript - Complete Guide

"This guide is a living compendium documenting the most important patterns and recipes on how to use React (and its Ecosystem) in a functional style using TypeScript. It will help you make your code completely type-safe while focusing on inferring the types from implementation so there is less noise coming from excessive type annotations and it's easier to write and maintain correct types in the long run."

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What's new?

:tada: Now updated to support TypeScript v4.6 :tada: :rocket: _Updated to typesafe-actions@5.x :rocket:

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Goals

• Complete type safety (with --strict flag) without losing type information downstream through all the layers of our application (e.g. no type assertions or hacking with any type)
• Make type annotations concise by eliminating redundancy in types using advanced TypeScript Language features like Type Inference and Control flow analysis
• Reduce repetition and complexity of types with TypeScript focused complementary libraries

React, Redux, Typescript Ecosystem

• typesafe-actions - Typesafe utilities for "action-creators" in Redux / Flux Architecture
• utility-types - Collection of generic types for TypeScript, complementing built-in mapped types and aliases - think lodash for reusable types.
• react-redux-typescript-scripts - dev-tools configuration files shared between projects based on this guide

Examples

• Todo-App playground: Codesandbox
• React, Redux, TypeScript - RealWorld App: Github | Demo

Playground Project

Check out our Playground Project located in the /playground folder. It contains all source files of the code examples found in the guide. They are all tested with the most recent version of TypeScript and 3rd party type-definitions (like @types/react or @types/react-redux) to ensure the examples are up-to-date and not broken with updated definitions (It's based on create-react-app --typescript).

Playground project was created so that you can simply clone the repository locally and immediately play around with all the component patterns found in the guide. It will help you to learn all the examples from this guide in a real project environment without the need to create complicated environment setup by yourself.

Contributing Guide

You can help make this project better by contributing. If you're planning to contribute please make sure to check our contributing guide: CONTRIBUTING.md

Funding

You can also help by funding issues. Issues like bug fixes or feature requests can be very quickly resolved when funded through the IssueHunt platform.

I highly recommend to add a bounty to the issue that you're waiting for to increase priority and attract contributors willing to work on it.

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🌟 - New or updated section

Table of Contents

• React Types Cheatsheet
  • React.FC<Props> | React.FunctionComponent<Props>
  • React.Component<Props, State>
  • React.ComponentType<Props>
  • React.ComponentProps<typeof XXX>
  • React.ReactElement | JSX.Element
  • React.ReactNode
  • React.CSSProperties
  • React.XXXHTMLAttributes<HTMLXXXElement>
  • React.ReactEventHandler<HTMLXXXElement>
  • React.XXXEvent<HTMLXXXElement>
• React
• Function Components - FC
  • - Counter Component
  • - Counter Component with default props
  • - Spreading attributes in Component
• Class Components
  • - Class Counter Component
  • - Class Component with default props
• Generic Components
  • - Generic List Component
• Hooks
  • - useState
  • - useContext
  • - useReducer
• Render Props
  • - Name Provider Component
  • - Mouse Provider Component
• Higher-Order Components
  • - HOC wrapping a component
  • - HOC wrapping a component and injecting props
  • - Nested HOC - wrapping a component, injecting props and connecting to redux 🌟
• Redux Connected Components
  • - Redux connected counter
  • - Redux connected counter with own props
  • - Redux connected counter via hooks
  • - Redux connected counter with redux-thunk integration
• Context
  • ThemeContext
  • ThemeProvider
  • ThemeConsumer
  • ThemeConsumer in class component
• Redux
• Store Configuration
  • Create Global Store Types
  • Create Store
• Action Creators 🌟
• Reducers
  • State with Type-level Immutability
  • Typing reducer
  • Typing reducer with typesafe-actions
  • Testing reducer
• Async Flow with redux-observable
  • Typing epics
  • Testing epics
• Selectors with reselect
• Connect with react-redux
  • Typing connected component
  • Typing useSelector and useDispatch
  • Typing connected component with redux-thunk integration
• Configuration & Dev Tools
• Common Npm Scripts
• tsconfig.json
• TSLib
• ESLint
  • .eslintrc.js
• Jest
  • jest.config.json
  • jest.stubs.js
• Style Guides
  • react-styleguidist
• FAQ
• Ambient Modules
  • Imports in ambient modules
• Type-Definitions
  • Missing type-definitions error
  • Using custom d.ts files for npm modules
• Type Augmentation
  • Augmenting library internal declarations - using relative import
  • Augmenting library public declarations - using node_modules import
• Misc
  • - should I still use React.PropTypes in TS?
  • - when to use interface declarations and when type aliases?
  • - what's better default or named exports?
  • - how to best initialize class instance or static properties?
  • - how to best declare component handler functions?
• Tutorials & Articles
• Contributors

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Installation

Types for React & Redux

npm i -D @types/react @types/react-dom @types/react-redux

"react" - @types/react
"react-dom" - @types/react-dom
"redux" - (types included with npm package)*
"react-redux" - @types/react-redux

*NB: Guide is based on types for Redux >= v4.x.x.

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React Types Cheatsheet

React.FC<Props> | React.FunctionComponent<Props>

Type representing a functional component

const MyComponent: React.FC<Props> = ...

React.Component<Props, State>

Type representing a class component

class MyComponent extends React.Component<Props, State> { ...

React.ComponentType<Props>

Type representing union of (React.FC<Props> | React.Component<Props>) - used in HOC

const withState = 

(
  WrappedComponent: React.ComponentType

,
) => { ...

React.ComponentProps<typeof XXX>

Gets Props type of a specified component XXX (WARNING: does not work with statically declared default props and generic props)

type MyComponentProps = React.ComponentProps<typeof MyComponent>;

React.ReactElement | JSX.Element

Type representing a concept of React Element - representation of a native DOM component (e.g. `

), or a user-defined composite component (e.g.`)

const elementOnly: React.ReactElement = 

 || <MyComponent />;

React.ReactNode

Type representing any possible type of React node (basically ReactElement (including Fragments and Portals) + primitive JS types)

const elementOrPrimitive: React.ReactNode = 'string' || 0 || false || null || undefined || 

 || <MyComponent />;
const Component = ({ children: React.ReactNode }) => ...

React.CSSProperties

Type representing style object in JSX - for css-in-js styles

const styles: React.CSSProperties = { flexDirection: 'row', ...
const element = 

`

Type representing HTML attributes of specified HTML Element - for extending HTML Elements

```tsx
const Input: React.FC<Props & React.InputHTMLAttributes<HTMLInputElement>> = props => { ... }

<Input about={...} accept={...} alt={...} ... />

React.ReactEventHandler<HTMLXXXElement>

Type representing generic event handler - for declaring event handlers

const handleChange: React.ReactEventHandler<HTMLInputElement> = (ev) => { ... } 

<input onChange={handleChange} ... />

React.XXXEvent<HTMLXXXElement>

Type representing more specific event. Some common event examples: ChangeEvent, FormEvent, FocusEvent, KeyboardEvent, MouseEvent, DragEvent, PointerEvent, WheelEvent, TouchEvent.

const handleChange = (ev: React.MouseEvent<HTMLDivElement>) => { ... }

In code above React.MouseEvent<HTMLDivElement> is type of mouse event, and this event happened on HTMLDivElement

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React

Function Components - FC

- Counter Component

::codeblock='playground/src/components/fc-counter.tsx'::

⟩⟩⟩ demo

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- Counter Component with default props

::codeblock='playground/src/components/fc-counter-with-default-props.tsx'::

⟩⟩⟩ demo

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- Spreading attributes in Component

::codeblock='playground/src/components/fc-spread-attributes.tsx'::

[⟩⟩⟩ demo](https://piotrwitek.github.io/react-redux-typescr