typescript - global function in Ionic 2 / Angular 2

Question

How can I setup a global function that can be accessed throughout all views?

In app.component.ts I added a simple method

  openShare() {console.log("button clicked")} 

and then in my nav I have

  <button ion-button right (click)="openShare()">
  <ion-icon name="md-share"></ion-icon>
</button>

When I try to access this from any page I get the following.

self.context.openShare is not a function

It does however execute fine if I put it directly in the constructor (e.g this.openShare(); ), but when calling from any page using a (click) function it just doesn't work.

Is app.component.ts not global? I thought this is where I would place it, but maybe I am missing something.

Basically its a function for a simple button on the nav, I need it to be global though since its used on every page.

Any help would be appreciated, still figuring Ionic 2 out.

Answer 1

You can use Directive.

Try as follows.

Put the following code in separate directive file. (social-sharing.directive.ts);

import { Directive, HostListener } from '@angular/core';

@Directive({
  selector: '[socialSharing]'
})
export class SocialSharing {

  constructor() { }

  @HostListener('click') onClick() {
    // Your click functionality
  }
}

Import it into app.module.ts and than add to declarations.

In HTML, just add attribute to any element which is the selector in your directive file.

<button ion-button right socialSharing>
 <ion-icon name="md-share"></ion-icon>
</button>

Additional Info:

Passing values from component to directive.

home.html

  <button ion-button right [socialSharing]="property">
    <ion-icon name="md-share"></ion-icon>
  </button>

home.component.ts

 export class HomePage {

   property: string = 'some url';
    constructor() {}
 }

social-sharing.directive.ts

Import Input along with others from @angular/core.

import { Directive, Input, HostListener } from '@angular/core';

@Directive({
   selector: '[socialSharing]'
})

export class SocialSharing {
  @Input('socialSharing') str: string;

  constructor() {}

  @HostListener('click') onClick() {
     console.log(this.str);
  }
};

  ngAfterInit() {
     console.log(this.str);
  };
}

Using Element in Directive:

social-sharing.directive.ts

Import ElementRef along with others from @angular/core

 import { Directive, ElementRef, HostListener } from '@angular/core';

 @Directive({
   selector: '[socialSharing]'
 })

 export class SocialSharing {

   // Add ElementRef to constructor

   constructor(el: ElementRef) {};

   ngOnInit() {
      let elRef = this.el.nativeElement;
      console.log(elRef.innerHTML);        
   };
 }