在构建使用Firebase的角应用时，如何处理所有可观察到的东西

Question

我已经构建了一些具有Angular和Firebase的应用程序，我刚刚启动了一个新应用。我对其他人如何使用可观察到的数据打交道感兴趣。在我的特定应用程序中，我需要使用可观察的可观察到从URL获取参数，检查用户是否经过身份验证，并从Firebase获取2个不同的对象。我需要先检查Auth，然后从URL获取参数，以便我可以找到Firebase对象的位置。过去，我刚刚做了类似可观察的订阅的巢穴。

ngOnInit() {
    this.af.auth.subscribe(auth => {
      if (auth) {
        this.uid = auth.uid;
        this.af.database.list('objectives', {
          query: {
            orderByChild: 'AuthorID',
            equalTo: auth.uid
          }
        }).subscribe(objectives => {
          console.log(objectives);
          this.allObjectives = objectives;
        })
      } else {
        this.router.navigate(['login'])
      }
    })
  }

现在，我必须将参数和另一个呼叫添加到firebase。我已经尝试使用RXJS的CommineLatest，但是看起来我可以使用一个可观察到的数据以在另一个可观察到的数据。我的问题是，有人在没有嵌套订阅的情况下解决了类似问题？

下面是我的软件包。JSON文件

{
  "name": "wdw-hunt",
  "version": "0.0.0",
  "license": "MIT",
  "scripts": {
    "ng": "ng",
    "start": "ng serve",
    "build": "ng build",
    "test": "ng test",
    "lint": "ng lint",
    "e2e": "ng e2e"
  },
  "private": true,
  "dependencies": {
    "@angular/common": "^2.4.0",
    "@angular/compiler": "^2.4.0",
    "@angular/core": "^2.4.0",
    "@angular/forms": "^2.4.0",
    "@angular/http": "^2.4.0",
    "@angular/platform-browser": "^2.4.0",
    "@angular/platform-browser-dynamic": "^2.4.0",
    "@angular/router": "^3.4.0",
    "angular2-cookie": "^1.2.6",
    "angularfire2": "^2.0.0-beta.8",
    "bootstrap": "^3.3.7",
    "core-js": "^2.4.1",
    "firebase": "^3.9.0",
    "hammer-timejs": "^1.1.0",
    "hammerjs": "^2.0.8",
    "ng2-bootstrap": "^1.4.2",
    "ng2-simple-page-scroll": "^2.0.0",
    "rxjs": "^5.1.0",
    "zone.js": "^0.7.6"
  },
  "devDependencies": {
    "@angular/cli": "1.0.0-rc.2",
    "@angular/compiler-cli": "^2.4.0",
    "@types/jasmine": "2.5.38",
    "@types/node": "~6.0.60",
    "codelyzer": "~2.0.0",
    "firebase-cli": "^1.2.0",
    "firebase-tools": "^3.5.0",
    "jasmine-core": "~2.5.2",
    "jasmine-spec-reporter": "~3.2.0",
    "karma": "~1.4.1",
    "karma-chrome-launcher": "~2.0.0",
    "karma-cli": "~1.0.1",
    "karma-coverage-istanbul-reporter": "^0.2.0",
    "karma-jasmine": "~1.1.0",
    "karma-jasmine-html-reporter": "^0.2.2",
    "protractor": "~5.1.0",
    "ts-node": "~2.0.0",
    "tslint": "~4.5.0",
    "typescript": "^2.3.2"
  }
}

下面是我的tsconfig

{
  "compilerOptions": {
    "sourceMap": true,
    "declaration": false,
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "target": "es5",
    "lib": [
      "es2016",
      "dom"
    ],
    "outDir": "../out-tsc/app",
    "module": "es2015",
    "baseUrl": "",
    "types": []
  },
  "exclude": [
    "test.ts",
    "**/*.spec.ts"
  ]
}

Answer 1

这就是我的方式

后卫：

import {Injectable} from '@angular/core';
import {ActivatedRouteSnapshot, CanActivate, Router, RouterStateSnapshot} from '@angular/router';
import {Observable} from 'rxjs/Observable';
import {AngularFire} from 'angularfire2';
import {isNullOrUndefined} from 'util';
@Injectable()
export class OverviewGuard implements CanActivate {
  constructor(private af: AngularFire, private router: Router) {
  }
  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
    return this.af.auth.map(auth => {
      if (isNullOrUndefined(auth)) {
        this.router.navigate(['/login']);
        return false;
      } else {
        return true;
      }
    });
  }
}

一些提供商：

import {Injectable} from '@angular/core';
import {AngularFire} from 'angularfire2';
import {Observable} from 'rxjs/Observable';
  @Injectable()
  export class JobProvider {
    constructor(private af: AngularFire) {
    }
    public getSomething(): Observable<Something> {
      return this.getUserDb()
        .switchMap(path => this.af.database.object(`${path}/something`));
    }
    private getUserDb(): Observable<string> {
      return this.af.auth
        .map(auth => `/debug/users/${auth.uid}`);
    }
  }