Oh, I thought you could use this in an Angular template because it's a Javascript built-in function, but it seems you can't. In this case you will have to implement a function to treat the parameters before sending them. You'll have to do something like this in the template:
(ionChange)="topicChanged()">
You will need to return Javascript code in your PHP method along with the template. This code should implement the function, something like this:
this.topicChanged = () => {
this.updateContent({
languagegiz: this.languagegiz,
topicgiz: JSON.stringify(this.CONTENT_OTHERDATA.topicgiz),
});
};
I hope this fixes your problem
Cheers,
Dani