Dart wrapper library for facebook/react

Pub documentation

Getting started

If you are not familiar with the ReactJS library, read this react tutorial first.

To integrate in Dart project add dependency react to pubspec.yaml.

Include the native javascript react and react_dom libraries (provided with this library for compatibility reasons) in index.html and create element where you'll mount the react component you'll create.

<html>
  <head>
    <script async src="packages/react/react.js"></script>
    <script async src="packages/react/react_dom.js"></script>
    <script async type="application/dart" src="your_app_name.dart"></script>
    <script async src="packages/browser/dart.js"></script>
  </head>
  <body>
    <div id="content">Here will be react content</div>
  </body>
</html>

If it fits the needs of your application better, you may alternatively load the concatenated minified react and react_dom libraries in a single file:

<script async src="packages/react/react_with_react_dom_prod.js"></script>

Initialize React in our Dart application. Mount simple component into '#content' div.

import 'dart:html';
import 'package:react/react_client.dart' as react_client;
import 'package:react/react.dart';
import 'package:react/react_dom.dart' as react_dom;

main() {
  // This should be called once at the beginning of the application
  react_client.setClientConfiguration();
  var component = div({}, "Hello world!");
  react_dom.render(component, querySelector('#content'));
}

Inverse method to rendering component is unmountComponentAtNode

  react_dom.unmountComponentAtNode(querySelector('#content'));

Using browser native elements

If you are familiar with React (without JSX extension) React-dart shouldn't surprise you much. All elements are defined as functions that take props as first argument and children as optional second argument. props should implement Map and children is either one React element or List with multiple elements.

div({"className": "somehing"}, [
  h1({"style": {"height": "20px"}}, "Headline"),
  a({"href":"something.com"}, "Something"),
  "Some text"
])

For event handlers you must provide function that take SyntheticEvent (defined in this library).

div({"onClick": (SyntheticMouseEvent e) => print(e)})

Defining custom elements

Define custom class that extends Component and implements at least render.

import 'package:react/react.dart';
class MyComponent extends Component {
  render() => div({}, "MyComponent");
}

Register this class so React can recognize it.

var myComponent = registerComponent(() => new MyComponent());

Use this registered component similarly as native elements.

react_dom.render(myComponent({}), querySelector('#content'));
// or
div({}, [
  myComponent({})
])

Warning: registerComponent should be called only once per component and lifetime of application.

Custom element with props

var myComponent = registerComponent(() => new MyComponent());
class MyComponent extends Component {
  render() => div({}, props['text']);
}
myComponent({"text":"Somehting"})

Creating components with richer interface than just props and children and with type control

typedef MyComponentType({String headline, String text});

var _myComponent = registerComponent(() => new MyComponent());

MyComponentType myComponent = ({headline, text}) =>
    _myComponent({'headline':headline, 'text':text});

class MyComponent extends Component {
  get headline => props['headline'];
  get text => props['text'];
  render() =>
    div({},[
      h1({}, headline),
      span({}, text),
    ]);
}

void main() {
  react_client.setClientConfiguration();
  react_dom.render(
    myComponent(headline: "My custom headline",
                text: "My custom text"),
    querySelector('#content')
  );
}

Using refs and findDOMNode

Proper usage of refs here is a little bit different from usage in react. You can specify a ref name in component props and then call ref method to get the referenced element. Return values for Dart components, DOM components and JavaScript components are different. For a Dart component, you get an instance of the Dart class of the component. For primitive components (like DOM elements), you get the DOM node. For JavaScript composite components, you get a ReactElement representing the react component.

If you want to work with DOM nodes of dart or JS components instead, you can call top level method findDOMNode on anything the ref returns.

var DartComponent = registerComponent(() => new _DartComponent());
class _DartComponent extends Component {
  var someData = 11;
  render() => div({});
}
var ParentComponent = registerComponent(() => new _ParentComponent());
class _ParentComponent extends Component {
  render() =>
    div({},[
      input({"ref": "input"}),
      DartComponent({"ref": "dart"})
    ]);
  componentDidMount() {
    InputElement input = ref("input"); // Returns the DOM node.

    _DartComponent dartRef = ref("dart"); // Returns instance of _DartComponent
    dartRef.someData; // you can call methods or get values from it
    react_dom.findDOMNode(dartRef); // return div element rendered from _DartComponent

    react_dom.findDOMNode(this); // return root dom element rendered from this component
  }
}

Geocodes Example

For more robust example take a look at example/geocodes/geocodes.dart.

Life-cycle methods of a component

These are quite similar to React life-cycle methods, so refer to React tutorial for further explanation/spec. Their signatures in Dart are as:

class MyComponent extends Component {
  void componentWillMount() {}
  void componentDidMount() {}
  void componentWillReceiveProps(newProps) {}
  bool shouldComponentUpdate(nextProps, nextState) => true;
  void componentWillUpdate(nextProps, nextState) {}
  void componentDidUpdate(prevProps, prevState) {}
  void componentWillUnmount() {}
  Map getInitialState() => {};
  Map getDefaultProps() => {};
  render() => div({}, props['text']);
}

Testing using React Test Utilities

lib/react_test_utils.dart is a Dart wrapper for the React TestUtils library allowing for tests to be made for React components in Dart.

Here is an example of how to use React TestUtils within a Dart test.

import 'package:test/test.dart';
import 'package:react/react.dart' as react;
import 'package:react/react_client.dart' as react_client;
import 'package:react/react_dom.dart' as react_dom;
import 'package:react/react_test_utils.dart' as react_test_utils;

class MyTestComponent extends react.Component {
  getInitialState() => {'text': 'testing...'};
  render() {
    return react.div({}, [
        react.button({'onClick': (e) => setState({'text': 'success'})}),
        react.span({'className': 'spanText'}, state['text'])
    ]);
  }
}

var myTestComponent = react.registerComponent(() => new MyTestComponent());

void main() {
  react_client.setClientConfiguration();

  test('should click button and set span text to "success"', () {
    var component = react_test_utils.renderIntoDocument(myTestComponent({}));

    // Find button using tag name
    var buttonElement = react_test_utils.findRenderedDOMComponentWithTag(
        component, 'button');

    // Find span using class name
    var spanElement = react_test_utils.findRenderedDOMComponentWithClass(
        component, 'spanText');

    var buttonNode = react_dom.findDOMNode(buttonElement);
    var spanNode = react_dom.findDOMNode(spanElement);

    // Span text should equal the initial state
    expect(spanNode.text, equals('testing...'));

    // Click the button and trigger the onClick event
    react_test_utils.Simulate.click(buttonNode);

    // Span text should change to 'success'
    expect(spanNode.text, equals('success'));
  });
}

To test the Dart wrapper, take a look at test/react_test_utils_test.dart.

Libraries

react

A Dart library for building UI using ReactJS.

react.test_utils

react_client

react_client.js_interop_helpers

Utilities for reading/modifying dynamic keys on JavaScript objects and converting Dart Maps to JavaScript objects.

react_client.react_interop

JS interop classes for main React JS APIs and react-dart internals.

react_dom

react_dom_server

react_server

react_test