일기장 무지개

import { Component, createElement } from 'react';
import { Text, View } from 'react-native';

export default class App extends Component<undefined, { i: number, j: number }> {
  constructor(props: undefined) {
    super(props);
    this.state = { i: 0, j: 0 };
  }

  componentDidMount() {
    this.setState({ i: setInterval(() => this.setState({ j: (this.state.j + 1) % 7 }), 3000)})
  }

  componentWillUnmount() {
    clearInterval(this.state.i);
  }

  render() {
    const Colors = ['red', 'orange', 'yellow', 'lime', 'cyan', 'blue', 'purple'];
    return createElement(
      View,
      {
        style: {
          backgroundColor: Colors[this.state.j],
          flex: 1
        }
      }
    );
  }
}