Google Analytics Service

analytics.service.ts

import { HttpClient, HttpHeaders } from '@angular/common/http';
import { Injectable } from '@angular/core';
import { NavigationEnd } from '@angular/router';
import { isDefined } from 'lib/util';

let singletonInstance: AnalyticsService;
export const analyticsServiceSingleton: Function = (): AnalyticsService => singletonInstance;

export interface EventParams {
  action: string;
  label?: string;
  newSession?: boolean;
  value?: number;
}

// tslint:disable:no-console
@Injectable()
export class AnalyticsService {
  private active: boolean = false;
  private currentUser: string;
  private gaCode: string;
  private appVersion: string;
  private clientid: string;

  public constructor(private http: HttpClient) {
    singletonInstance = this;
  }
  /**
   * @param  {string} gaCode - Google Analytics code
   * @param  {string} user - Username
   * @param  {string} uniqueId - Unique Id for the device
   * @returns void
   */
  public SetupGoogleAnalytics(gaCode: string, user: string, uniqueId: string): void {
    this.clientid = uniqueId;
    this.currentUser = user;
    this.gaCode = gaCode;
    this.active = true;
  }

  public async view(title: string, path?: string): Promise<boolean> {
    return await this.write({ t: 'pageview', dp: path, dt: title, dl: location.pathname });
  }

  public setAppVersion(version?: string): void {
    if (isDefined(version)) {
      this.appVersion = version;
    }
  }

  public async event(
    category: string,
    action: string,
    label?: string,
    value?: number,
    newSession?: boolean
  ): Promise<boolean> {
    return await this.write({ t: 'event', ec: category, ea: action, el: label, ev: value });
  }

  public error(description: string): void {
    this.write({ t: 'exception', exd: description, exf: 0 });
    console.log(`Analytics Error: ${description}`);
  }

  /**
   * Tracks the page view based on Angular route taken. Formats the route title better for tracking
   * @param  {NavigationEnd} route
   */
  public viewRoute(route: NavigationEnd): string {
    try {
      const tabIdx: number = route.url.indexOf(':') + 1;
      let title: string = route.url.substring(tabIdx).replace(')', '');
      title = decodeURIComponent(title);
      title = this.toTitleCase(title);
      return title;
    } catch {
      // Analytics are not important enough to break the app. So catch all
    }
  }

  /**
   * Set the user for Analytics
   * @param  {string} user
   * @returns void
   */
  public setUser(user: string): void {
    this.currentUser = user || 'guest';
  }

  private toTitleCase(input: string): string {
    return input.length === 0
      ? ''
      : input.replace(/\w\S*/g, (txt: string) => txt[0].toUpperCase() + txt.substr(1).toLowerCase());
  }

  private async write(ob: any): Promise<boolean> {
    if (!this.active) {
      console.log('analytics is disabled');
      return false;
    }
    const standard: object = {
      v: '1',
      tid: this.gaCode,
      cid: this.clientid,
      uid: this.currentUser,
      an: 'MyApplication',
      av: this.appVersion
    };
    const data: string = `${this.serialize(standard)}&${this.serialize(ob)}`;
    const options: any = { headers: new HttpHeaders({ 'Content-Type': 'text/plain' }), responseType: 'text' };
    try {
      await this.http.post('https://www.google-analytics.com/collect', data, options).toPromise();
    } finally {
      return true;
    }
  }

  private serialize(obj: object): string {
    const str: Array<string> = [];
    for (const p in obj) {
      if (obj.hasOwnProperty(p)) {
        if (obj[p] !== undefined) {
          str.push(`${encodeURIComponent(p)}=${encodeURIComponent(obj[p])}`);
        }
      }
    }
    return str.join('&');
  }
}