From: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Date: Wed, 20 Jun 2018 19:22:06 +0200
Subject: Add an helper to detect current desktop

We will differentiate some behavior depending on current desktop. Add an
helper to centralize the current desktop detection.
Forwarded: not-needed
Origin: ubuntu
===================================================================
---
 js/js-resources.gresource.xml |  1 +
 js/misc/desktop.js            | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+)
 create mode 100644 js/misc/desktop.js

diff --git a/js/js-resources.gresource.xml b/js/js-resources.gresource.xml
index 76b5f95..5babd0f 100644
--- a/js/js-resources.gresource.xml
+++ b/js/js-resources.gresource.xml
@@ -13,6 +13,7 @@
 
     <file>misc/config.js</file>
     <file>misc/extensionUtils.js</file>
+    <file>misc/desktop.js</file>
     <file>misc/fileUtils.js</file>
     <file>misc/dbusUtils.js</file>
     <file>misc/gnomeSession.js</file>
diff --git a/js/misc/desktop.js b/js/misc/desktop.js
new file mode 100644
index 0000000..8bdca57
--- /dev/null
+++ b/js/misc/desktop.js
@@ -0,0 +1,33 @@
+// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
+
+const GLib = imports.gi.GLib;
+
+// current desktop doesn't change unless we restart the shell or control
+// the env variable. It's safe to cache matching result
+const _currentDesktopsMatches = new Map();
+
+// is:
+// @name: desktop string you want to assert if it matches the current desktop env
+//
+// The function examples XDG_CURRENT_DESKTOP and return if the current desktop
+// is part of that desktop string.
+//
+// Return value: if the environment isn't set or doesn't match, return False
+// otherwise, return True.
+function is(name) {
+    if (!_currentDesktopsMatches.size) {
+        const desktopsEnv = GLib.getenv('XDG_CURRENT_DESKTOP');
+        if (!desktopsEnv) {
+            _currentDesktopsMatches.set(name, false);
+            return false;
+        }
+
+        const desktops = desktopsEnv.split(':');
+        desktops.forEach(d => _currentDesktopsMatches.set(d, true));
+
+        if (!_currentDesktopsMatches.size)
+            _currentDesktopsMatches.set(name, _currentDesktopsMatches.has(name));
+    }
+
+    return !!_currentDesktopsMatches.get(name);
+}