do-more-in-render-example.js

// bad
componentWillMount() {
    this.setState({
        computedFoo: compute(this.props.foo)
    });
},
componentWillReceiveProps(nextProps) {
    this.setState({
        computedFoo: compute(nextProps.foo)
    });
},
render() {
    return <div>{ this.state.computedFoo }</div>;
}


// better
render() {
    var computedFoo = compute(this.props.foo);
    return <div>{ computedFoo }</div>;
}