react：条件运算、list等基础知识

条件运算

render () {const blackBtn &＃61; <button classNamee&＃61;"btn">black btn</button>const whiteBtn &＃61; <button classNamee&＃61;"btn">white btn</button>if (this.state.theme) {return blackBtn} else {return whiteBtn}return <div>{ this.state.theme &＃61;&＃61;&＃61; &＃39;black&＃39; ? blackBtn : whiteBtn }</div>return <div>{ this.state.theme && blackBtn }</div>
}


list

render () {return <ul>{this.state.list.map((item, index) &＃61;> {return <li key&＃61;{item.id}>index: {index};title: {item.title}</li>})}</ul>
}