react-live: A JavaScript repository from scottyeck

React Live

A production-focused playground for live editing React code

React Live brings you the ability to render React components and present the user with editable source code and live preview. It supports server-side rendering and comes in a tiny bundle, thanks to Bublé and a Prism.js-based editor.

The library is structured modularly and lets you style its components as you wish and put them where you want.

Usage

Install it with npm install react-live and try out this piece of JSX:

import {
  LiveProvider,
  LiveEditor,
  LiveError,
  LivePreview
} from 'react-live'

<LiveProvider code="<strong>Hello World!</strong>">
  <LiveEditor />
  <LiveError />
  <LivePreview />
</LiveProvider>

Demo

https://react-live.philpl.com/

FAQ

How does it work?

It takes your code and transpiles it through Bublé, while the code is displayed using Prism.js. The transpiled code is then rendered in the preview component, which does a fake mount, if the code is a component.

Easy peasy!

What code can I use?

The code can be one of the following things:

React elements, e.g. <strong>Hello World!</strong>
React pure functional components, e.g. () => <strong>Hello World!</strong>
React component classes

If you enable the noInline prop on your LiveProvider, you’ll be able to write imperative code, and render one of the above things by calling render.

How does the scope work?

The scope prop on the LiveProvider accepts additional globals. By default it injects React only, which means that the user can use it in their code like this:

//                    ↓↓↓↓↓
class Example extends React.Component {
  render() {
    return <strong>Hello World!</strong>
  }
}

But you can of course pass more things to this scope, that will be available as variables in the code. Example:

import styled from 'styled-components'

const scope = {styled}

const code = `
  const Header = styled.div\`
    color: palevioletred;
    font-size: 18px;
  \`

  render(<Header>I'm styled!</Header>)
`

<LiveProvider code={code} scope={scope} noInline={true}>
  <LiveEditor />
  <LiveError />
  <LivePreview />
</LiveProvider>

API

<LiveProvider />

This component provides the context for all the other ones. It also transpiles the user’s code! It supports these props, while passing all others through to a <div />:

Name	PropType	Description
code	PropTypes.string	The code that should be rendered, apart from the user’s edits
scope	PropTypes.object	Accepts custom globals that the `code` can use
mountStylesheet	PropTypes.bool	Mounts the stylesheet for the prism editor (Default: `true`)
noInline	PropTypes.bool	Doesn’t evaluate and mount the inline code (Default: `false`)
transformCode	PropTypes.func	Accepts and returns the code to be transpiled, affording an opportunity to first transform it.

Apart from these props it attaches the .react-live CSS class to its div. All subsequent components must be rendered inside a provider, since they communicate using one.

By default this component will render a <style /> tag for the Prism styling. You can decide not to render it and include the react-live.css file instead.

The noInline option kicks the Provider into a different mode, where you can write imperative-style code and nothing gets evaluated and mounted automatically. Your example will need to call render with valid JSX elements.

<LiveEditor />

This component renders the editor that displays the code. It is built using Prism.js and a Content Editable. It accepts these props for styling:

Name	PropType	Description
className	PropTypes.string	An additional class that is added to the Content Editable
ignoreTabKey	PropTypes.bool	Makes the editor ignore tab key presses so that keyboard users can tab past the editor without getting stuck
style	PropTypes.object	Additional styles for the Content Editable
onChange	PropTypes.func	Accepts a callback that is called when the user makes changes

This component renders a Prism.js editor underneath it and also renders all of Prism’s styles inside a style tag. The editor / content editable has an additional .react-live-editor CSS class.

<LiveError />

This component renders any error that occur while executing the code, or transpiling it. It passes through any props to its div and also attaches the .react-live-error CSS class to it.

Note: Right now the component unmounts, when there’s no error to be shown.

<LivePreview />

This component renders the actual component, that the code generates, inside an error boundary. It passes through any props to its div and also attaches the .react-live-preview CSS class to it.

withLive

The withLive method creates a higher-order component, that injects the live-editing context provided by LiveProvider into a component, as the live prop.

The context's shape is as follows:

Name	Type	Description
code	string	Reflects the code that is passed in as the `code` prop
error	string	An error that the code has thrown when it was previewed
onError	function	A callback that, when called, changes the error to what's passed as the first argument
onChange	function	A callback that accepts new code and transpiles it
element	React.Element	The result of the transpiled code that is previewed

Note: The code prop doesn't reflect the up-to-date code, but the code prop, that is passed to the LiveProvider. This is due to the fact that the Editor is an uncontrolled input for the reason of managing the contentEditable element efficiently.

Using this HOC allows you to add new components to react-live, or replace the default ones, with a new desired behaviour.

Comparison to component-playground

There are multiple options when it comes to live, editable React component environments. Formidable actually has two first class projects to help you out: component-playground and react-live. Let's briefly look at the libraries, use cases, and factors that might help in deciding which is right for you.

Here's a high-level decision tree:

If you want fast and easy setup and integration, then component-playground may be the ticket!
If you want a smaller bundle, SSR, and more flexibility, then react-live is for you!

Here are the various factors at play:

Build: component-playground uses babel-standalone, react-live uses bublé. (Note: react-live might make transpiler customizable in the future).
Bundle size: component-playground has a larger bundle, but uses a more familiar editor setup. react-live is smaller, but more customized editor around prism.
Ease vs. flexibility: react-live is more modular/customizable, while component-playground is easier/faster to set up.
SSR: component-playground is not server-side renderable, react-live is.
Extra features: component-playground supports raw evaluation and pretty-printed output out-of-the-box, while react-live does not.
Error handling: component-playground might have more predictable error handling than react-live in some cases (due to react-dom, although this might change with React 16).

scottyeck/react-live