Угловой вход
<input (change)="saverange()"/>
GutoTrosla
<input (change)="saverange()"/><input [value]="foo" (change)="changeFn($event)">
<input [ngModel]="bar" (ngModelChange)="modelChangeFn($event)">export class MyClassName implements OnInit,OnChanges {
@Input() documents: Document[] = [];
.....
ngOnChanges(changes: SimpleChanges){
console.log("changes ", changes)
if(changes.documents){
console.log("changes2 ", changes)
}
}