                        课程
                    
                        /前端开发
                        
                            /React.JS
                        
                        /React实战--打造画廊应用（上）

Warning: Each child in an array or iterator should have a unique "key" prop. Check the render method of GalleryByReactApp. See https://fb.me/react-warning-keys for more information.

请有大神知道这两条报错的原因么？

render: function () {
    var imgFigures = [],
        controllerUnits = [];

    imageDatas.forEach(function (value, index) {

        if (!this.state.imgsArrangeArr[index]) {
            this.state.imgsArrangeArr[index] = {
                pos: {
                    left: 0,
                    top: 0
                }
            };
        }

        imgFigures.push(<ImgFigure data={value} ref={'imgFigure' + index} arrange={this.state.imgsArrangeArr[index]}/>);
    }.bind(this));


    return (
        <section className="stage" ref="stage">
            <section className="img-sec">
                {imgFigures}
            </section>
            <nav className="controller-nav">
                {controllerUnits}
            </nav>
        </section>
    );
}