how to clear state in react hooks

1const { useState } = React;
2
3function signupUser() {
4  return new Promise(resolve => {
5    setTimeout(resolve, 1000);
6  });
7}
8
9const initialState = {
10  username: "",
11  email: "",
12  password: "",
13  passwordConfirmation: ""
14};
15
16const Signup = () => {
17  const [
18    { username, email, password, passwordConfirmation },
19    setState
20  ] = useState(initialState);
21
22  const clearState = () => {
23    setState({ ...initialState });
24  };
25
26  const onChange = e => {
27    const { name, value } = e.target;
28    setState(prevState => ({ ...prevState, [name]: value }));
29  };
30
31  const handleSubmit = e => {
32    e.preventDefault();
33    signupUser().then(clearState);
34  };
35
36  return (
37    <form onSubmit={handleSubmit}>
38      <div>
39        <label>
40          Username:
41          <input value={username} name="username" onChange={onChange} />
42        </label>
43      </div>
44      <div>
45        <label>
46          Email:
47          <input value={email} name="email" onChange={onChange} />
48        </label>
49      </div>
50      <div>
51        <label>
52          Password:
53          <input
54            value={password}
55            name="password"
56            type="password"
57            onChange={onChange}
58          />
59        </label>
60      </div>
61      <div>
62        <label>
63          Confirm Password:
64          <input
65            value={passwordConfirmation}
66            name="passwordConfirmation"
67            type="password"
68            onChange={onChange}
69          />
70        </label>
71      </div>
72      <button>Submit</button>
73    </form>
74  );
75};
76
77ReactDOM.render(<Signup />, document.getElementById("root"));