Classes and prototypes ?

[Treyarch]

Hello,

I've built a first version of my clockface with the 4.0 SDK recently and I was using classes with prototypes and I updated to the 4.1 SDK 3 days ago and for some reasons I can't compile anymore.

I get " App: Unhandled exception: TypeError: Expected a function. " whenever I try to call a prototype function in my classes.

Does anyone have any ideas as to why this is happening ?

[LiamFitbit]

Do you have some code that worked before which now doesn't we could look at? It's hard to help without specifics unfortunately.

[Treyarch]

Yes sure :

Here's a sample class that used to work and does not anymore :

export function RetroSettings(){
    this.settings_type = "json";
    this.settings_file = "settings.json";
}

RetroSettings.prototype.load = function() {
    this.settings = this.loadSettings();
    //console.log(`Settings loaded : ${JSON.stringify(this.settings.classe)}`);
    this.applyTheme(this.settings.background, this.settings.foreground);
    this.applyCharacter(this.settings.classe);
    this.applyClockSize(this.settings.size);

    // Listen for the onmessage event
    messaging.peerSocket.onmessage = evt => {
        //console.log(`App received: ${JSON.stringify(evt.data)}`);
        if(evt.data.classe){
            this.applyCharacter(evt.data.classe);
        }
        if(evt.data.background && evt.data.foreground){
            this.applyTheme(evt.data.background, evt.data.foreground);
        }
        if(evt.data.size){
            this.applyClockSize(evt.data.size);
        }
    };
    // Register for the unload event
    appbit.onunload = this.saveSettings;
};

The loadSettings method throws this error now : 

App: Unhandled exception: TypeError: Expected a function. ? at app/retro/RetroSettings.js:28,1

This is just and example but every prototype methods throw this error now.

Works on SDK 4.0 but not 4.1

[LiamFitbit]

Is that the whole file? Just trying to figure out which line the error refers to.

[LiamFitbit]

I just tried this code in both SDK 4.0 and SDK 4.1 and saw both log messages with no errors:

function MyClass() {
  console.log('ctor');
}

MyClass.prototype.load = function() {
  console.log('load');
}

const mc = new MyClass();
mc.load();

So I think your example in isolation perhaps isn't enough to reproduce whatever the issue is.

[Treyarch]

Hi,

I'm wondering if it comes from the "this" keyword inside the class itself for some reason.

Calling the method outside works but calling it from inside the class does not...

Weird...

[Treyarch · Accepted solution]

Ok, I've figured it out.

Basically it's my fault, I was calling the "this" keyword inside another class that did not have the method I was trying to execute. The call was mixed up inside a class that add a single call to a system class which explains the mix up !

Eveything is working fine now !