Object.create as used in the plus plug illuminator, is used to copy and modify a subobject - works on 0.14.4

object_create_works.js

function reportConfigError(res, ec, em) {
    console.log("Config update error", ec, em);
}

let onColorConfig = { 
  rgb: [100, 0, 0],
//  rgb: [0, 0, 100],
  brightness: 80
};

let uiConfig = Shelly.getComponentConfig("plugs_ui");

uiConfig.leds.colors["switch:0"].on = onColorConfig;

let offColorConfig = Object.create( onColorConfig );
   
offColorConfig.brightness = 20;
   
uiConfig.leds.colors["switch:0"].off = offColorConfig;

Shelly.call( "PLUGS_UI.SetConfig", { config: uiConfig}, reportConfigError );