import { Component } from '@angular/core' ; @ Component ( { templateUrl : 'root-page.html' } ) export class RootPage { homeIcon = 'home' ; isActive = false ; iconIndex = 0 ; icons = [ 'home' , 'star' , 'ios-alert' , 'ios-alert-outline' , 'md-alert' , 'logo-apple' ] ; btnIcon : string ; dynamicColor : string = 'danger' ; constructor ( ) { this . btnIcon = this . icons [ 0 ] ; } updateIcon ( ) { this . iconIndex ++ ; if ( this . iconIndex >= this . icons . length ) { this . iconIndex = 0 ; } this . btnIcon = this . icons [ this . iconIndex ] ; } }