#Dart wrapper library for facebook/react
##Getting started
If you are not familiar with React library read react tutorial first.
To integrate in Dart project add dependency react to pubspec.yaml.
Include native react library (provided with this library for compatibility reasons) to 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 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>Initialize React in our Dart application. Mount simple component into '#content' div.
import 'dart:html';
import 'package:react/react_client.dart' as reactClient;
import 'package:react/react.dart';
main() {
//this should be called once at the begging of application
reactClient.setClientConfiguration();
var component = div({}, "Hello world!");
render(component, querySelector('#content'));
}Inverse method to rendering component is unmountComponentAtNode
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.
render(myComponent({}), querySelector('#content'));
// or
div({}, [
myComponent({})
])Warning: registerComponent should be called only once per component and lifetime of application.
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() {
reactClient.setClientConfiguration();
render(
myComponent(headline: "My custom headline",
text: "My custom text"),
querySelector('#content')
);
}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 value for dart components and for javascript components is different. For dart component, you get an instance of dart class of the component. For js components (like DOM elements), you get instance of jsObject representing the react component. If you want to work with DOM nodes instead of a component, 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(root) {
var inputRef = ref("input"); //return react jsObject
InputElement input = findDOMNode(inputRef); // return InputElement in dom
_DartComponent dartRef = ref("dart"); //return instance of _DartComponent
dartRef.someData; // you can call methods or get values from it
findDOMNode(dartRef); //return div element rendered from _DartComponent
findDOMNode(this); //return root dom element rendered from this component
}
}
For more robust example take a look at example/geocodes/geocodes.dart.
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(/*DOMElement*/rootNode) {}
void componentWillReceiveProps(newProps) {}
bool shouldComponentUpdate(nextProps, nextState) => true;
void componentWillUpdate(nextProps, nextState) {}
void componentDidUpdate(prevProps, prevState, /*DOMElement */ rootNode) {}
void componentWillUnmount() {}
Map getInitialState() => {};
Map getDefaultProps() => {};
render() => div({}, props['text']);
}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:unittest/unittest.dart';
import 'package:react/react.dart' as react;
import 'package:react/react_client.dart' as reactClient;
import 'package:react/react_test_utils.dart' as reactTestUtils;
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() {
reactClient.setClientConfiguration();
test('should click button and set span text to "success"', () {
var component = reactTestUtils.renderIntoDocument(myTestComponent({}));
// Find button using tag name
var buttonElement = reactTestUtils.findRenderedDOMComponentWithTag(
component, 'button');
// Find span using class name
var spanElement = reactTestUtils.findRenderedDOMComponentWithClass(
component, 'spanText');
var buttonNode = reactTestUtils.getDomNode(buttonElement);
var spanNode = reactTestUtils.getDomNode(spanElement);
// Span text should equal the initial state
expect(spanNode.text, equals('testing...'));
// Click the button and trigger the onClick event
reactTestUtils.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.
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