extension.js

import Gio from 'gi://Gio';
import GObject from 'gi://GObject';

import * as Main from 'resource:///org/gnome/shell/ui/main.js';
import {Extension} from 'resource:///org/gnome/shell/extensions/extension.js';

let signal_overlay_key = null;
let original_signal_overlay_key = null;
let settings = null;

// Overview functions
function overview_visible() {
    return Main.overview.visibleTarget;
}

function overview_hide() {
    if (Main.overview.animationInProgress) {
        // prevent accidental re-show
    } else if (overview_visible()) {
        Main.overview.hide();
    }
}

// Overlay-key
var overlay_key_action = null;

function overlay_key() {
    console.log("overlay key detected");
    overview_hide();
    let proc = new Gio.Subprocess({argv: overlay_key_action.split(' ')});
    proc.init(null);
}

function overlay_key_changed(settings) {
    overview_hide();
    overlay_key_action = settings.get_string("overlay-key-action");
}

export default class SuperKey extends Extension {

	enable() {
	
	    settings = this.getSettings();
	
	    // Load overlay key action and keep it up to date with settings
	    overlay_key_changed(settings);
	    settings.connect("changed::overlay-key-action", () => {
	        overlay_key_changed(settings);
	    });
	
	    // Block original overlay key handler
	    original_signal_overlay_key = GObject.signal_handler_find(global.display, { signalId: "overlay-key" });
	    if (original_signal_overlay_key !== null) {
	        global.display.block_signal_handler(original_signal_overlay_key);
	    }
	
	    // Connect modified overlay key handler
	    const A11Y_SCHEMA = 'org.gnome.desktop.a11y.keyboard';
	    const STICKY_KEYS_ENABLE = 'stickykeys-enable';
	    let _a11ySettings = new Gio.Settings({ schema_id: A11Y_SCHEMA });
	    signal_overlay_key = global.display.connect("overlay-key", () => {
	        if (!_a11ySettings.get_boolean(STICKY_KEYS_ENABLE))
	            overlay_key();
	    });
	}

	disable() {
	
	    // Disconnect modified overlay key handler
	    if (signal_overlay_key !== null) {
	        global.display.disconnect(signal_overlay_key);
	        signal_overlay_key = null;
	    }
	
	    // Unblock original overlay key handler
	    if (original_signal_overlay_key !== null) {
	        global.display.unblock_signal_handler(original_signal_overlay_key);
	        original_signal_overlay_key = null;
	    }
	
	    settings =  null;
	}
	
}