I am using ionic4/angular4.the changes made to the username should reflect in all pages.
<ion-input type="text" placeholder="Profile Name" [readonly]="isReadOnly" ngModel name="profile"
#nameCtrl="ngModel" required minlength="3" pattern="^[A-Za-zÀ-ÿ ,.'-]+$" (focusout)="out_profile()" #name
no-padding>
</ion-input>