问题描述
这是 React 组件中非常常见的模式：
handleTextFieldChange(event)
{
const name = event.currentTarget.name;
this.setState({[name]: event.currentTarget.value})
}
什么 Javascript 语法可以用来对 React 钩子做同样的事情？
即可能是这样的：
handleTextFieldChange(event)
{
const name = event.currentTarget.name;
this.set[name](event.currentTarget.value);
}
1楼
您可以使用单个useState和一个对象的默认值，该对象包含所有输入值，并像您习惯使用类组件一样更新。
例子
const { useState } = React; function App() { const [state, setState] = useState({ email: "", password: "" }); function onChange(event) { const { name, value } = event.target; setState(prevState => ({ ...prevState, [name]: value })); } return ( <div> <input value={state.email} name="email" onChange={onChange} /> <input value={state.password} name="password" onChange={onChange} /> </div> ); } ReactDOM.render(<App />, document.getElementById("root"));
<script src="https://unpkg.com/react@16/umd/react.development.js"></script> <script src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script> <div id="root"></div>
2楼
这样的事情怎么样？
function handleTextFieldChange(mySetFunction, event) {
const value = event.currentTarget.value;
mySetFunction(value);
}
<TextField
placeholder="Email"
name="passwordResetEmailAddress"
onChange={(e) => handleTextFieldChange(setPasswordResetEmailAddress, e)}
>
{passwordResetEmailAddress}
</TextField>
我已经测试过它并且它有效。
3楼
class Yup extends React.Component {
state = {
first: "",
second: ""
};
handleTextFieldChange = ({ target: { name, value } }) =>
this.setState({ [name]: value });
render() {
const { first, second } = this.state;
return (
<div>
<p>{first}</p>
<p>{second}</p>
<input type="text" name="first" onChange={this.handleTextFieldChange} />
<input
type="text"
name="second"
onChange={this.handleTextFieldChange}
/>
</div>
);
}
}
和钩子一样
function Yup() {
const [{ first, second }, setState] = useState({ first: "", second: "" });
function handleTextFieldChange({ target: { name, value } }) {
setState(prevState => ({ ...prevState, [name]: value }));
}
return (
<div>
<p>{first}</p>
<p>{second}</p>
<input type="text" name="first" onChange={handleTextFieldChange} />
<input type="text" name="second" onChange={handleTextFieldChange} />
</div>
);
}
4楼
您可以通过接收更新状态函数作为 onChange 函数中的参数来动态更新目标字段的状态。
例子
import React, { useState } from "react";
const App = () => {
const [email, setEmail] = useState("");
const [password, setPassword] = useState("");
const onChangeHandler = (setIdentifierState, event) => {
setIdentifierState(event.target.value);
};
return (
<div>
<p>{"Email: " + email}</p>
<p>{"Password: " + password}</p>
<input
type="text"
placeholder="email"
onChange={onChangeHandler.bind(this, setEmail)}
/>
<input
type="text"
placeholder="password"
onChange={onChangeHandler.bind(this, setPassword)}
/>
</div>
);
};
export default App;
5楼
我最近在将组件从类转换为函数时解决了同样的问题。 我最终创建了一个可以指向单独状态挂钩的对象：
const textStates = {};
const setTextStates= {};
for (var name of names) {
let [textState, setTextState] = useState("");
textStates[name] = textState;
setTextStates[name] = setTextState;
}
6楼
我是这样解决的（比@VikR 提供的解决方案稍微动态一点）
const [title, setTitle] = useState("");
const [desc, setDesc] = useState("");
const [video, setVideo] = useState("");
const handleChange = setter => event => {
const value = event.target.value;
//special cases
if (setter === setVideo) {
setInvalidVideo(!ReactPlayer.canPlay(value))
}
setter(value)
}
然后在我的代码中：
<TextField fullWidth value={title} type="date"
label={t('service.ticket.add.title')}
placeholder={t('service.ticket.add.titlePh')}
onChange={handleChange(setTitle)} variant="outlined"/>