Why is does angular require modular division for a resetting counter?

I am looking for an explanation for the following behaviour.

So I am doing a tutorial located here.

The tutorial asks you to make a counter component which counts to 25 if the number is greater then 25 and then resets to 1 via setter function.

I thought the setter should be written like this:

set counter(val: number) {
this._counter = val;
if(this._counter > 25) this.counter = 1;
}
private _counter = 1;


AppComponent is implemented as follows:

export class AppComponent {
title = 'sample-app';
counter = 10;
inc() {
this.counter++;
}
}


This doesn't work it counts up to 25 and then stays at 1.

The code from the tutorial does work however:

set counter(val: number) {

this._counter = val || 0;
if (val > 25) this._counter = val % 25;


}

private _counter: number = 1;

That doesn't look right to me... as I can imagine values that would not assign 1 to the counter.

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