Reactをes6で使う場合のbindの問題 ref: http://qiita.com/cubdesign/items/ee8bff7073ebe1979936

file0.html

save(e){
    this.props // undefined　になる
}
render (){
    return (
        <button onClick={this.save} />保存</button>
    );
}

file1.html

save = function (e){
    this.props // undefined ではない
}
render = function (){
    return (
        <button onClick={this.save} />保存</button>
    );
}

file2.html

constructor() {
    super();
    this.save = this.save.bind(this);
}
render = function (){
    return (
        <button onClick={this.save} />保存</button>
    );
}

file3.html

render = function (){
    return (
        <button onClick={this.save.bind(this)} />保存</button>
    );
}

file4.html

render = function (){
    return (
        <button onClick={(event) => this.save(event)} />保存</button>
    );
}

file5.html

render = function (){
    return (
        <button onClick={::this.save} />保存</button>
    );
}