prop-types

What is prop-types?

The prop-types package is used for runtime type checking of the props that a React component receives. It helps in documenting the intended types of properties passed to components and catching errors in development if a component receives props of incorrect types.

What are prop-types's main functionalities?

Typechecking with PropTypes

This code demonstrates how to use PropTypes to define type requirements for a React component's props. It specifies that the 'name' prop is required and must be a string, 'age' must be a number, 'onButtonClick' should be a function, 'children' should be a React node, 'style' should be an object with numeric values, and 'items' should be an array of strings.

{"Component.propTypes = { name: PropTypes.string.isRequired, age: PropTypes.number, onButtonClick: PropTypes.func, children: PropTypes.node, style: PropTypes.objectOf(PropTypes.number), items: PropTypes.arrayOf(PropTypes.string) };"}

Default Prop Values

This code provides default values for props in a React component. If 'age', 'onButtonClick', or 'items' are not provided by the parent component, they will default to 30, a no-op function, and an empty array, respectively.

{"Component.defaultProps = { age: 30, onButtonClick: () => {}, items: [] };"}

Custom Validators

This code shows how to define a custom validator for a prop. If the 'customProp' does not match the specified pattern, a validation error will be thrown.

{"Component.propTypes = { customProp: function(props, propName, componentName) { if (!/matchme/.test(props[propName])) { return new Error('Validation failed!'); } } };"}

Other packages similar to prop-types

typescript

TypeScript is a superset of JavaScript that adds static type definitions. Unlike prop-types, TypeScript checks types at compile time rather than at runtime. This can help catch errors earlier in the development process and provides a more robust type system.

flow-bin

Flow is a static type checker for JavaScript developed by Facebook. Similar to TypeScript, it checks types at compile time. Flow can be used with React to ensure that props and state are of the correct types, offering a similar level of type safety to TypeScript.

io-ts

io-ts is a runtime type system for IO decoding/encoding. It is similar to prop-types in that it performs runtime type checking, but it also provides the ability to define types for data structures and validate data at the boundaries of the system, such as API responses.

tcomb

tcomb is a library for type checking and DDD (Domain Driven Design). It allows you to define types and interfaces and can be used for prop validation in React components. It offers more features than prop-types, such as refinement types and combinators, but it is also more complex.

README

prop-types

Runtime type checking for React props and similar objects.

Installation

npm install --save prop-types

Importing

import PropTypes from 'prop-types'; // ES6
var PropTypes = require('prop-types'); // ES5 with npm

If you prefer a <script> tag, you can get it from window.PropTypes global:

<!-- development version -->
<script src="https://unpkg.com/prop-types/prop-types.js"></script>
 
<!-- production version -->
<script src="https://unpkg.com/prop-types/prop-types.min.js"></script>

Development and Production Versions

In production, all validator functions are replaced with empty functions that throw an error. This is done to optimize the bundle size.

Don’t call the validator functions manually in your code. React automatically calls PropTypes validators declared on your components in development version, and it won’t call them in production.

If you use a bundler like Browserify or Webpack, don’t forget to follow these instructions to correctly bundle your application in development or production mode. Otherwise you’ll ship unnecessary code to your users.

Usage

Refer to the React documentation for more information.

Migrating from React.PropTypes

Check out Migrating from React.PropTypes for details on how to migrate to prop-types from React.PropTypes