Гист для статьи: "Еще раз о паттернах проектирования в Javascript es6 (часть 2)"

facade.js

class WebsocketInteraction {
  constructor(url, port) {
    this.url = url;
    this.port = port;
  }

  connect() {
    return new Promise((resolve) => {
      this.connection = new WebSocket(`wss://${this.url}:${this.port}`);
      this.connection.onopen = (e) => {
        console.log('connected', e);
        resolve();
      };
    });
  }

  disconnect() {
    return new Promise((resolve) => {
      this.connection.close();
      this.connection.onclose = (e) => {
        console.log('disconnected', e);
        resolve();
      };
    });
  }

  sendMessage(message) {
    return new Promise((resolve) => {
      this.connection.send(message);
      this.connection.onmessage = (e) => {
        console.log(e);
        resolve();
      };
    });
  }
}

class HttpInteraction {
  constructor(url) {
    this.url = url;
  }

  sendRequest(message, method) {
    return fetch(`https://${this.url}`, {
      method,
      body: JSON.stringify(message),
    })
      .then((res) => res.json())
      .then((post) => {
        console.log(post);
      });
  }
}

class ServerInteraction {
  request(type, message, method) {
    if (type === 'websocket') {
      const server = new WebsocketInteraction('echo.websocket.org', 443);
      return server.connect()
        .then(() => server.sendMessage(message))
        .then(() => server.disconnect());
    } if (method && type === 'http') {
      const server = new HttpInteraction('jsonplaceholder.typicode.com/posts');
      return server.sendRequest(message, method);
    }
    throw new Error('No method provided!');
  }
}

const testing = async () => {
  const server = new ServerInteraction();

  await server.request('websocket', 'test-message');
  console.log('=========================');
  await server.request('http', {
    title: 'foo',
    body: 'bar',
    userId: 1,
  }, 'POST');
};

testing();