React.js: Composing components to create tabs

Question

I’m trying to make a tabs component. TabsSwitcher and TabsPanel must be separate components so they could be used anywhere in DOM, e.g. TabsSwitcher doesn’t have to be followed by TabsPanel.

To make it work, I need to somehow connect these components. Furthermore, TabsSwitcher must be able to tell TabsPanel when a tab was clicked.

/** @jsx React.DOM */

var TabsExample = React.createClass({
    render: function() {
        var tabs = [
            {title: 'first', content: 'Content 1'},
            {title: 'second', content: 'Content 2'}
        ];
        return <div>
            <TabsSwitcher items={tabs}/>
            <TabsContent items={tabs}/>
        </div>;
    }
});

var TabsSwitcher = React.createClass({
    render: function() {
        var items = this.props.items.map(function(item) {
            return <a onClick={this.onClick}>{item.title}</a>;
        }.bind(this));
        return <div>{items}</div>;
    },
    onClick: function(e) {
        // notify TabsContent about the click
    }
});

var TabsContent = React.createClass({
    render: function() {
        var items = this.props.items.map(function(item) {
            return <div>{item.content}</div>;
        });
        return <div>{items}</div>;
    }
});

React.renderComponent(
    <TabsExample/>,
    document.body
);

What’s the best way to do it?

---

Solution: http://jsfiddle.net/NV/5YRG9/

Answer 1

The React docs cover this in detail in "Communicate Between Components" and "Multiple Components". The gist is that the parent should pass a function as a prop to the child, and the child should call that function as a callback when it needs to:

var TabsExample = React.createClass({
    handleTabClick: function(item) {
        // Do something with item, maybe set it as active.
    },
    render: function() {
        var tabs = [
            {title: 'first', content: 'Content 1'},
            {title: 'second', content: 'Content 2'}
        ];
        return <div>
            <TabsSwitcher items={tabs} onTabClick={this.handleTabClick}/>
            <TabsContent items={tabs}/>
        </div>;
    }
});

var TabsSwitcher = React.createClass({
    render: function() {
        var items = this.props.items.map(function(item) {
            return <a onClick={this.onClick.bind(this, item)}>{item.title}</a>;
        }.bind(this));
        return <div>{items}</div>;
    },
    onClick: function(item) {
        this.props.onTabClick(item);
    }
});

For the TabsContent component, you should move the tabs into the TabsExample state so React can automatically re-render for you when they change. Since TabsSwitcher and TabsContent are passed the tabs in the render method, React knows they are dependent on the tabs and will re-render when the state changes:

var TabsExample = React.createClass({
    getInitialState: function() {
        return {
            activeTabId: 1,
            tabs: [
                {title: 'first', content: 'Content 1', id: 1},
                {title: 'second', content: 'Content 2', id: 2}
            ]
        };
    };
    handleTabClick: function(item) {
        // Call `setState` so React knows about the updated tab item.
        this.setState({activeTabId: item.id});
    },
    render: function() {
        return (
            <div>
                <TabsSwitcher items={this.state.tabs}
                              activeItemId={this.state.activeTabId}
                              onTabClick={this.handleTabClick}/>
                <TabsContent items={this.state.tabs}
                             activeItemId={this.state.activeTabId}/>
            </div>
        );
    }
});