Angular cast select value to int

Question

Use [ngValue] instead of "value":

<select [(ngModel)]="selected.isConnected" id="etat">
    <option [ngValue]="0">Not connected</option>
    <option [ngValue]="1">Connected</option>
</select> 

If you want cast it within formChanged() method (Which you haven't provided yet). You should use + symbol as shown below,

formChanged(): void {
    selected.isConnected = +selected.isConnected;
    ...
}

No, sadly you're forced to parse it on your own in the formChanged() method, since you always get a string back from the select.

You could try it with something like this:

formChanged(): void {
    selected.isConnected = parseInt(selected.isConnected);
    // ...
}