我已经检索了使用useState
存储在对象数组中的数据,然后将数据输出到表单字段中。现在我希望能够在输入时更新字段(状态)。
我见过人们更新数组中属性的状态的示例,但从未见过更新对象数组中状态的示例,所以我不知道该怎么做。我已将对象的索引传递给回调函数,但我不知道如何使用它来更新状态。
// sample data structure
const data = [
{
id: 1,
name: 'john',
gender: 'm'
}
{
id: 2,
name: 'mary',
gender: 'f'
}
]
const [data, setData] = useState([]);
const updateFieldChanged = index => e => {
console.log('index: ' + index);
console.log('property name: '+ e.target.name);
setData() // ??
}
return (
<React.Fragment>
{data.map((data, index) => {
<li key={data.name}>
<input type="text" name="name" value={data.name} onChange={updateFieldChanged(index)} />
</li>
})}
</React.Fragment>
)
最佳答案
具体操作方法如下:
// sample data structure
/* const data = [
{
id: 1,
name: 'john',
gender: 'm'
}
{
id: 2,
name: 'mary',
gender: 'f'
}
] */ // make sure to set the default value in the useState call (I already fixed it)
const [data, setData] = useState([
{
id: 1,
name: 'john',
gender: 'm'
}
{
id: 2,
name: 'mary',
gender: 'f'
}
]);
const updateFieldChanged = index => e => {
console.log('index: ' + index);
console.log('property name: '+ e.target.name);
let newArr = [...data]; // copying the old datas array
// a deep copy is not needed as we are overriding the whole object below, and not setting a property of it. this does not mutate the state.
newArr[index] = e.target.value; // replace e.target.value with whatever you want to change it to
setData(newArr);
}
return (
<React.Fragment>
{data.map((datum, index) => {
<li key={datum.name}>
<input type="text" name="name" value={datum.name} onChange={updateFieldChanged(index)} />
</li>
})}
</React.Fragment>
)
关于javascript - 如何更新 React Hooks 中对象数组中的状态 `onChange`,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/55987953/