title: Property 'catch' does not exist on type 'PromiseLike<void>'
body: <p>Im an ionic beginner and was following some tutorials and as I was trying to catch an error I ran into some typescript problems...</p>
  
  <blockquote>
    <p>Property 'catch' does not exist on type 'PromiseLike'</p>
  </blockquote>
  
  <p>Must be an outdated code or something.</p>
  
  <p>Here where the problem is. It happens to every page I try to use the catch.</p>
  
  <pre><code>.then(() =&gt; { resolve(true);})
  .catch((err) =&gt; {reject(err);})
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/m3FIx.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/m3FIx.png" alt="Here is a screenshot"></a></p>
  
  <p><a href="https://i.stack.imgur.com/TlhJA.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TlhJA.png" alt="Here is another screenshot"></a></p>
  
  <p>//////////////////UPDATE//////////
  Here is the package.json file. Im trying to create a firebase chat app.</p>
  
  <pre><code>{
    "name": "chat",
    "version": "0.0.1",
    "author": "Ionic Framework",
    "homepage": "http://ionicframework.com/",
    "private": true,
    "scripts": {
      "clean": "ionic-app-scripts clean",
      "build": "ionic-app-scripts build",
      "lint": "ionic-app-scripts lint",
      "ionic:build": "ionic-app-scripts build",
      "ionic:serve": "ionic-app-scripts serve"
    },
    "dependencies": {
      "@angular/common": "5.0.3",
      "@angular/compiler": "5.0.3",
      "@angular/compiler-cli": "5.0.3",
      "@angular/core": "5.0.3",
      "@angular/forms": "5.0.3",
      "@angular/http": "5.0.3",
      "@angular/platform-browser": "5.0.3",
      "@angular/platform-browser-dynamic": "5.0.3",
      "@ionic-native/core": "4.4.0",
      "@ionic-native/file": "^4.4.2",
      "@ionic-native/file-chooser": "^4.4.2",
      "@ionic-native/file-path": "^4.4.2",
      "@ionic-native/splash-screen": "4.4.0",
      "@ionic-native/status-bar": "4.4.0",
      "@ionic/storage": "2.1.3",
      "angularfire2": "^5.0.0-rc.4",
      "cordova-plugin-file": "^5.0.0",
      "cordova-plugin-filechooser": "^1.0.1",
      "cordova-plugin-filepath": "^1.1.0",
      "firebase": "^4.7.0",
      "ionic-angular": "3.9.2",
      "ionicons": "3.0.0",
      "rxjs": "5.5.2",
      "sw-toolbox": "3.6.0",
      "zone.js": "0.8.18"
    },
    "devDependencies": {
      "@ionic/app-scripts": "3.1.4",
      "typescript": "2.4.2"
    },
    "description": "An Ionic project",
    "cordova": {
      "plugins": {
        "cordova-plugin-file": {},
        "cordova-plugin-filechooser": {},
        "cordova-plugin-filepath": {}
      }
    }
  }
  </code></pre>