&#39;PromiseLike&#39;类型中不存在属性&#39;catch&#39; <void> “

Question

Im an ionic beginner and was following some tutorials and as I was trying to catch an error I ran into some typescript problems...

Property 'catch' does not exist on type 'PromiseLike'

Must be an outdated code or something.

Here where the problem is. It happens to every page I try to use the catch.

.then(() => { resolve(true);})
.catch((err) => {reject(err);})

//////////////////UPDATE////////// Here is the package.json file. Im trying to create a firebase chat app.

{
  "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": {}
    }
  }
}

Answer 1

The issue is probably because the "then" on push returns a ThenableReference which in return causes to return a "PromiseLike". Instead, if you choose to use "set" on push, it will return a then. So the method should read like this

 let promise = new Promise((resolve, reject) => { this.firerequest.child(request.recipient).push().set( { sender: request.sender } ).then(() => { resolve({ success: true }) }).catch((error) => { reject(error); }) }) return promise; 

Your excerpt from Raja Yogan's chat, so I just pasted code from a different provider. Hope it helps.