我正在通过我的项目学习reactjs和react hook
篮球比赛中每位球员的得分
我希望应用程序执行以下操作:
- 在输入字段中输入一个数字
- 检查该号码是否已存在
- 如果是:根据单击的按钮,将1、2、3添加到totPoints
- 如果否:加上数字和totPoints=1、torPoints=2或totPoints=3。取决于单击的按钮
2a(2b(如果否:添加数字和其中之一,totPoints=1,或torPoints=2,或totPoints=3。取决于点击哪个按钮
从youtube 得到想法后,我正在重写我的代码
const [number, setNumber] = useState('');
const [totPoints, setTotPoints] = useState(0);
const [scorers, setScorers] = useState([
{id: nanoid(4), number: 9, totPoints: 99},
{id: nanoid(4), number: 1, totPoints: 11},
{id: nanoid(4), number: 15, totPoints: 9},
]);
const onePointScoredHandler = () => {
const players = [...scorers];
const existingScorer = players.find((player) => player.number === number);
if (existingScorer) {
console.log('exist');
} else {
console.log('new');
}
不幸的是,无论我在输入字段中输入什么数字,if(existingScorer)
都无法识别列表中已经存在的数字,而是console.log ('new')
这是因为number
状态是字符串,而player.number
是数字。您可以使用+
运算符将其转换为数字以正确比较它们:
const existingScorer = players.find((player) => player.number === +number);