Appending variable dynamically to this property

Question

I want to pass the item variable dynamic into this property e.g. If the item has value of 35 it will become this.BookingConfirmationFormsState35

onChange( event, item ){
   console.log( this.BookingConfirmationFormsState+item ); // Doesn't work
}

Answer 1

onChange( event, item ){
   console.log( this['BookingConfirmationFormsState' + item]);
}

Answer 2

You need to use bracket notation [] to access the dynamic property name:

this['BookingConfirmationFormsState' + item];

For item = 35, the above code is equivalent to:

this.BookingConfirmationFormsState35