class App extends Component {
  state = {
    name: '',
    username: '',
    location: '',
    password: '',
  }

  setValue = (fieldName) => (evt) => this.setState({ [fieldName]: evt.target.value });

  render() {
    const { name, username, location, password } = this.state;
    return (
      <div className="App">
        <p>Name: {name}</p>
        <input onChange={this.setValue('name')} value={name} />
        <p>Username: {username}</p>
        <input onChange={this.setValue('username')} value={username} />
        <p>Location: {location}</p>
        <input onChange={this.setValue('location')} value={location} />
        <p>Password</p>
        <input onChange={this.setValue('password')} value={password} />
      </div>
    )
  }
}