定义类型：

interface ObjectOf<V> { 
  [_: string]: V
}
class OrderItem { 
  uuid: string;
  amount: number;
  secondaryTotal: number;
  total: number;
  originalTotal: number;
  checked: boolean;
}

使用

interface State { 
	 promoList: { 
	    giftCheck:ObjectOf<OrderItem>
	    freeCheck:Array<OrderItem>
	  }
  }