@kiina/salesforce/src/chat.api.js

const { map, expand, retryWhen, tap, takeWhile } = require('rxjs/operators');

// const { BASE_URL, DEFAULT_HEADERS } = require('./constants');
const DEFAULT_TIMEOUT = 10000;

class ChatApi {

  constructor(config, driver = require('./requestDriver')) {
    if (!config) throw new Error('No config was given.');
    this.__config = config;
    this.__driver = driver;
  }

  __request(url, method, params = {}, body = {}, headers = {}) {
    return this.__driver.request({
      baseUrl: this.__config.baseURL,
      url,
      headers: { ...this.__config.defaultHeaders, ...headers },
      method,
      qs: { ...params, access_token: this.__token },
      body,
      json: true,
      timeout: DEFAULT_TIMEOUT
    });
  }

  createSession() {
    return this.__request('/chat/rest/System/SessionId', 'GET')
      .toPromise();
  }

  initializeChasitor(session, chasitor = {}) {
    const headers = {
      "X-LIVEAGENT-AFFINITY": session.affinityToken,
      "X-LIVEAGENT-SESSION-KEY": session.key,
      "X-LIVEAGENT-SEQUENCE": 1
    };
    const body = {
      ...chasitor,
      sessionId: session.id
    };
    return this.__request('/chat/rest/Chasitor/ChasitorInit', 'POST', {}, body, headers)
      .toPromise();
  }

  sendMessage(session, text) {
    const headers = {
      "X-LIVEAGENT-AFFINITY": session.affinityToken,
      "X-LIVEAGENT-SESSION-KEY": session.key
    };
    return this.__request('/chat/rest/Chasitor/ChatMessage', 'POST', {}, { text }, headers)
      .toPromise();
  }

  __readMessage(cursorId, headers) {
    return this.__request('/chat/rest/System/Messages', 'GET', { ack: cursorId }, {}, headers);
  }

  endChat(session){
    const headers = {
      "X-LIVEAGENT-AFFINITY": session.affinityToken,
      "X-LIVEAGENT-SESSION-KEY": session.key
    };
    return this.__request('/chat/rest/Chasitor/ChatEnd', 'POST', {}, {ChatEndReason:{reason: 'client closed window'}}, headers)
      .toPromise();
  }

  readMessages(session) {
    let cursorId = 0;
    const headers = {
      "X-LIVEAGENT-AFFINITY": session.affinityToken,
      "X-LIVEAGENT-SESSION-KEY": session.key
    };
    return this.__readMessage(cursorId, headers).pipe(
      expand(response => this.__readMessage(cursorId++, headers)),
      retryWhen(error$ => error$.pipe(
        tap(error => console.error(error.code)),
        takeWhile(error => error.code === "ESOCKETTIMEDOUT" || error.code === "ETIMEDOUT")
      )),
      map(data => data && data.messages || [])
    );
  }
}

module.exports = ChatApi;