There's another (uncommon) way of communicating between components: simply expose a method on the child component for the parent to call.
Say a list of todos, which upon clicking get removed. If there's only one unfinished todo left, animate it:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | var Todo = React.createClass({ render: function() { return <div onClick={this.props.onClick}>{this.props.title}</div>; }, //this component will be accessed by the parent through the `ref` attribute animate: function() { console.log('Pretend %s is animating', this.props.title); }});var Todos = React.createClass({ getInitialState: function() { return {items: ['Apple', 'Banana', 'Cranberry']}; }, handleClick: function(index) { var items = this.state.items.filter(function(item, i) { return index !== i; }); this.setState({items: items}, function() { if (items.length === 1) { this.refs.item0.animate(); } }.bind(this)); }, render: function() { return ( <div> {this.state.items.map(function(item, i) { var boundClick = this.handleClick.bind(this, i); return ( <Todo onClick={boundClick} key={i} title={item} ref={'item' + i} /> ); }, this)} </div> ); }});ReactDOM.render(<Todos />, mountNode); |
Alternatively, you could have achieved this by passing the todo an isLastUnfinishedItem prop, let it check this prop in componentDidUpdate, then animate itself; however, this quickly gets messy if you pass around different props to control animations.
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