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react-from-zero/10-example-app.html
2018-06-05 07:46:14 +02:00

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HTML

<!doctype html>
<title>10 Example App - React From Zero</title>
<script src="https://unpkg.com/react@15.4.2/dist/react.js"></script>
<script src="https://unpkg.com/react-dom@15.4.2/dist/react-dom.js"></script>
<script src="https://unpkg.com/@babel/standalone/babel.min.js"></script>
<div id="app"></div>
<script type="text/babel">
// An example of a simple React app
// It uses simple component functions for its stateless components
// and a complex component class to handle the interactions
// First we have the Task and TaskList
// They get all their data/state through their properties
// <TaskList>
// <Task text='Do something'/>
// <Task text='Do nothing'/>
// </TaskList>
// Task needs a text property
function Task(props) {
return <li>{props.text}</li>
}
// TaskList needs an array of Task in its children property
function TaskList(props) {
// Print the first element bold
return (
<ul>
<b key={0}>{props.children[0]}</b>
{props.children.slice(1)}
</ul>
)
}
// This component handles the input
// It needs to be a class, because the <input> element is stateful
var TaskInput = React.createClass({
getInitialState: function() {
return {value: ''}
},
// gets called when someone types into the <input> element
handleChange: function(e) {
this.setState({value: e.target.value})
},
// gets called when someone clicks the <button> element
handleAdd: function(e) {
if (!this.state.value) return
// call the function that was added into its onAdd property
this.props.onAdd(this.state.value)
// clear the state so the input is empy again after an add
this.setState({value: ''})
},
// renders the elements every time someone types or adds
render: function() {
return (
<div>
<input
placeholder='Enter Task .'
value={this.state.value}
onChange={this.handleChange}/>
<button onClick={this.handleAdd}>Add</button>
</div>
)
},
})
// The app keeps track of the current tasks in its state
var TodoApp = React.createClass({
getInitialState: function() {
return {tasks: []}
},
// this callback will be inserted into the onAdd property of the <TaskInput> component
handleAdd: function(task) {
// adding a new task
var tasks = [task].concat(this.state.tasks)
// this forces the <TodoApp> component to render
this.setState({tasks: tasks})
},
render: function() {
// create the list of <Task> components from the tasks array in the state
var taskElements = this.state.tasks.map(function(t, i) {
return <Task key={i} text={t}/>
})
// some simple styling
// and adding the add handler to the <TaskInput> component
return (
<div style={{width: 300, margin: 'auto'}}>
<TaskInput onAdd={this.handleAdd}/>
<TaskList>
{taskElements}
</TaskList>
</div>
)
},
})
var renderTarget = document.getElementById('app')
// we can use components directly
ReactDOM.render(<TodoApp/>, renderTarget)
</script>