onchange equivalent in angular2

You can use:

<input (input)="saverange()>

We can use Angular event bindings to respond to any DOM event. The syntax is simple. We surround the DOM event name in parentheses and assign a quoted template statement to it. -- reference

Since change is on the list of standard DOM events, we can use it:

(change)="saverange()"

---

In your particular case, since you're using NgModel, you could break up the two-way binding like this instead:

[ngModel]="range" (ngModelChange)="saverange($event)"

Then

saverange(newValue) {
  this.range = newValue;
  this.Platform.ready().then(() => {
     this.rootRef.child("users").child(this.UserID).child('range').set(this.range)
  })
} 

However, with this approach saverange() is called with every keystroke, so you're probably better off using (change).

In Angular you can define event listeners like in the example below:

<!-- Here you can call public methods from parental component -->
<input (change)="method_name()"> 

@Mark Rajcok gave a great solution for ion projects that include a range type input.

In any other case of non ion projects I will suggest this:

HTML:

<input type="text" name="points" #points maxlength="8" [(ngModel)]="range" (ngModelChange)="range=saverange($event, points)">

Component:

    onChangeAchievement(eventStr: string, eRef): string {

      //Do something (some manipulations) on input and than return it to be saved:

       //In case you need to force of modifing the Element-Reference value on-focus of input:
       var eventStrToReplace = eventStr.replace(/[^0-9,eE\.\+]+/g, "");
       if (eventStr != eventStrToReplace) {
           eRef.value = eventStrToReplace;
       }

      return this.getNumberOnChange(eventStr);

    }

The idea here:

1. Letting the (ngModelChange) method to do the Setter job:

   (ngModelChange)="range=saverange($event, points)

2. Enabling direct access to the native Dom element using this call:

   eRef.value = eventStrToReplace;