Alert not working

Ionic Framework ionic-v3
1

Please i have been trying to implement the Alert component in my ionic project but i keep getting this error (TypeError: Cannot read property ‘present’ of undefined), this happens when i insert the line of code (this.nav.present(alert):wink: at the end and without this code it won’t work. Below is my code

onConfirm() {
let alert = Alert.create({
title: ‘Attention’,
subTitle: ‘hey there’,
buttons: [“Yes”]
})
this.nav.present(alert);
}

The error that is showing on google chrome inspect element is attached

image
alert.PNG764×273 37.4 KB

Please help me with solution.

2

The error message is telling you exactly what is wrong. this.nav is undefined.

3

Sorry I don’t understand you when you say this.nav is not define, I think it is defined in the constructor like this (this.nav = nav), or is that not what you are referring to?

4

undefined is a primitive value in JavaScript. In the statement you mention, if the right hand side (“nav”) is undefined, so will be this.nav. Whereever you are getting nav from isn’t working.

5

I just figured where the problem is, in my export class i have something like this

export class AdmissionsPage {
static get parameters() {
return [[Platform]];
}

if i remove the static get parameters() it will work, like this
export class AdmissionsPage {

}.

The problem now is that i can’t remove those parameters because am using it to call inappbrowser plugin, pls do u have any idea on what i can do to keep those parameters and also have the alert working?

6

If you’re using TypeScript, just type it as a constructor argument:

class AdmissionsPage {
  constructor(private _plat:Platform) {
    _plat.ready().then(() => {
      // do stuff
    });
  }

  anotherMethod() {
    // this._plat is still visible here
  }
}

If your project is JavaScript, my only advice is “switch to TypeScript”, but perhaps somebody else will have other suggestions. I can’t stand JavaScript, and have done everything in my power to avoid it as much as possible.

7

ok thanks…i am using typescript, its working now…