React to Web Component

@r2wc/react-to-web-component converts React components to custom elements! It lets you share React components as native elements that don't require mounted being through React. The custom element acts as a wrapper for the underlying React component. Use these custom elements with any project that uses HTML even in any framework (vue, svelte, angular, ember, canjs) the same way you would use standard HTML elements.

@r2wc/react-to-web-component:

Works in all modern browsers. (Edge needs a customElements polyfill).
Is 1.11KB minified and gzipped.

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Basic Use

For basic usage, we will use this simple React component:

const Greeting = () => {
  return <h1>Hello, World!</h1>
}

With our React component complete, all we have to do is call r2wc and customElements.define to create and define our custom element:

import r2wc from "@r2wc/react-to-web-component"

const WebGreeting = r2wc(Greeting)

customElements.define("web-greeting", WebGreeting)

Now we can use <web-greeting> like any other HTML element!

<body>
  <h1>Greeting Demo</h1>

  <web-greeting></web-greeting>
</body>

Note that by using React 18, r2wc will use the new root API. If your application needs the legacy API, please use React 17

In the above case, the web-greeting custom element is not making use of the name property from our Greeting component.

Working with Attributes

By default, custom elements created by r2wc only pass properties to the underlying React component. To make attributes work, you must specify your component's props.

const Greeting = ({ name }) => {
  return <h1>Hello, {name}!</h1>
}

const WebGreeting = r2wc(Greeting, {
  props: {
    name: "string",
  },
})

Now r2wc will know to look for name attributes as follows:

<body>
  <h1>Greeting Demo</h1>

  <web-greeting name="Justin"></web-greeting>
</body>

For projects needing more advanced usage of the web components, see our programatic usage and declarative demos.

We also have a complete example using a third party library.

Setup

To install from npm:

npm install @r2wc/react-to-web-component

External Examples

Greeting example in CodeSandbox

Hello, world example (React17) in CodeSandbox

Example with all prop types in CodeSandbox

R2WC With Vite Header Example in CodeSandbox

External Blog Posts

R2WC with Vite View Post

R2WC with Create React App (CRA) View Post

How it works

Check out our full API documentation.

Under the hood, r2wc creates a CustomElementConstructor with custom getters/setters and life cycle methods that keep track of the props that you have defined. When a property is set, its custom setter:

re-renders the React component inside the custom element.
creates an enumerable getter / setter on the instance to save the set value and avoid hitting the proxy in the future.

Also:

Enumerable properties and values on the custom element are used as the props passed to the React component.
The React component is not rendered until the custom element is inserted into the page.

Tests

To run tests, first run:

npm run buildtests

This copies the root test file into each of the /tests/react* versioned folders, modifies the ReactDOM import for older versions, and installs the corresponding version of react in that directory.

Then run:

npm run test

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