我认为投票的答案仍然是正确的，但最近 React 发布了新的内置useReducer函数，用他们自己的话来说，就是
便于稍后响应操作重置状态
https://reactjs.org/docs/hooks-reference.html#usereducer
它还指出，当您具有涉及多个子值的复杂状态逻辑或下一个状态取决于前一个状态时，通常最好使用 useReducer。
在投票答案上使用相同的示例，您可以像这样使用 useReducer：
Javascript
import React, { useReducer } from "react";
const initialState = {
username: "",
email: "",
password: "",
passwordConfirmation: "",
};
const reducer = (state, action) => {
if (action.type === "reset") {
return initialState;
}
const result = { ...state };
result[action.type] = action.value;
return result;
};
const Signup = () => {
const [state, dispatch] = useReducer(reducer, initialState);
const { username, email, password, passwordConfirmation } = state;
const handleSubmit = e => {
e.preventDefault();
/* fetch api */
/* clear state */
dispatch({ type: "reset" });
};
const onChange = e => {
const { name, value } = e.target;
dispatch({ type: name, value });
};
return (
<form onSubmit={handleSubmit}>
<div>
<label>
Username:
<input value={username} name="username" onChange={onChange} />
</label>
</div>
<div>
<label>
Email:
<input value={email} name="email" onChange={onChange} />
</label>
</div>
<div>
<label>
Password:
<input
value={password}
name="password"
type="password"
onChange={onChange}
/>
</label>
</div>
<div>
<label>
Confirm Password:
<input
value={passwordConfirmation}
name="passwordConfirmation"
type="password"
onChange={onChange}
/>
</label>
</div>
<button>Submit</button>
</form>
);
};
export default Signup;
typescript
import React, { FC, Reducer, useReducer } from "react";
interface IState {
email: string;
password: string;
passwordConfirmation: string;
username: string;
}
interface IAction {
type: string;
value?: string;
}
const initialState: IState = {
email: "",
password: "",
passwordConfirmation: "",
username: "",
};
const reducer = (state: IState, action: IAction) => {
if (action.type === "reset") {
return initialState;
}
const result: IState = { ...state };
result[action.type] = action.value;
return result;
};
export const Signup: FC = props => {
const [state, dispatch] = useReducer<Reducer<IState, IAction>, IState>(reducer, initialState, () => initialState);
const { username, email, password, passwordConfirmation } = state;
const handleSubmit = (e: React.FormEvent) => {
e.preventDefault();
/* fetch api */
/* clear state */
dispatch({ type: "reset" });
};
const onChange = (e: React.ChangeEvent<HTMLInputElement>) => {
const { name, value } = e.target;
dispatch({ type: name, value });
};
return (
<form onSubmit={handleSubmit}>
<div>
<label>
Username:
<input value={username} name="username" onChange={onChange} />
</label>
</div>
<div>
<label>
Email:
<input value={email} name="email" onChange={onChange} />
</label>
</div>
<div>
<label>
Password:
<input
value={password}
name="password"
type="password"
onChange={onChange}
/>
</label>
</div>
<div>
<label>
Confirm Password:
<input
value={passwordConfirmation}
name="passwordConfirmation"
type="password"
onChange={onChange}
/>
</label>
</div>
<button>Submit</button>
</form>
);
};
请注意，我创建了这个reducer函数 const 以使其尽可能通用，但是您可以完全更改它并测试不同的操作类型（除了简单的状态属性名称）并在返回修改后的状态之前执行复杂的计算。上面提供的链接中有一些示例。