React vs Vue

react.js

class UserView extends React.Component {
constructor(props) {
  super(props);
  this.state = {
    user: undefined
  };
  fetch(`/api/user/${this.props.userId}`)
  .then((res) => res.json())
  .then((user) => {
    this.setState({ user });
  });
},
render() {
  const user = this.state.user;
  return (
    <div>
    { user ? (
      <p>User name: {user.name}</p>
    ) : (
      <p>Loading…</p>
    ) }
      </div>
    );
  }
};
UserView.propTypes = {
  userId: PropTypes.number
};

vue.js

const UserView = {
  template: `
    <div>
    <p v-if="user">User name: {{ user.name }}</p>
    <p v-else>Loading...</p>
    </div>`,
  props: {
    userId: {
      type: Number,
      required: true
    }
  },
  data: () => ({
    user: undefined
  },
  mounted() {
    fetch(`/api/user/${this.userId}`)
    .then((res) => res.json())
    .then((user) => {
      this.user = user;
    });
  }
};