Newbie needs constructor that takes an object with named properties

[CraigFoote]

I’m writing an extension where I’ve created a class that extends St.BoxLayout, to act as a panel in the extension’s dialog. I want to instantiate it from extension.js by calling it’s constructor and pass in information. Passing a simple value parameter produces the error:
Argument to the constructor of StatusPanel should be an object with properties to set

I expect I’ll need to call it like this:
const panel = new StatusPanel({param1: value});

What should the constructor look like? I’ve tried:

constructor(obj){
  this.param1 = obj['param1'];
}

…but it produces the same error. Any help appreciated.

[ptomato (Philip Chimento)]

Your expectation of how to construct StatusPanel looks correct to me.

If the properties are registered as GObject properties (with GObject.ParamSpec), you can just omit the constructor and the _init() method on your class, and it will do the right thing.

If they are not registered as GObject properties (just regular JS properties), you can define an _init() method that removes the non-GObject properties before chaining up:

_init({ param1 = someDefaultValue, ...otherProps } = {}) {
  super._init(otherProps);
  this.param1 = param1;
}