why is my input setter called even without changes

I have typical setter/getter for an input in my code, as I want to execute a function when the value changes, but somehow it is fired without input changes

private _myInput: string[]: [];
@Input()
get myInput(): string[] {
  return this._myInput;
}
set myInput(myInput[]) {
  this._myInput = myInput;
  this.doStuff();
}

the problem doStuff method is called too many times because i receive an empty list in a constant way. I only want the setter get fired when there is changes

Every time you get an emtpy list and assign it to the input variable (this part of code we don't see) the input is changing. It will get a new object (list), which is empty. For you, there is no change in the data, but for Angular there is a change in the reference.

In order to get this working, simply check in the setter method if the list contains any element. If yes, then call doStuff. Or even better: check for it in the parent component and set the input variable only if the list isn't empty.