cleanup: Use object destructuring where possible

ES6's destructuring is a nice way of assigning a variable in a concise way,
without duplicating the name of the object property. Use it consistently
where possible.

https://gitlab.gnome.org/GNOME/gnome-shell-extensions/merge_requests/91

extensions/auto-move-windows/extension.js

@@ -2,7 +2,7 @@
 // Start apps on custom workspaces
 /* exported init enable disable */
 
-const Shell = imports.gi.Shell;
+const { Shell } = imports.gi;
 
 const ExtensionUtils = imports.misc.extensionUtils;
 const Main = imports.ui.main;

extensions/window-list/extension.js

@@ -751,7 +751,7 @@ const WindowList = GObject.registerClass({
             'keyboard-visible-changed',
             (o, state) => {
                 Main.layoutManager.keyboardBox.visible = state;
-                let keyboardBox = Main.layoutManager.keyboardBox;
+                let { keyboardBox } = Main.layoutManager;
                 keyboardBox.visible = state;
                 if (state) {
                     Main.uiGroup.set_child_above_sibling(
@@ -858,7 +858,7 @@ const WindowList = GObject.registerClass({
 
         let children = this._windowList.get_children();
         let [, childWidth] = children[0].get_preferred_width(-1);
-        let spacing = this._windowList.layout_manager.spacing;
+        let { spacing } = this._windowList.layout_manager;
 
         let workspace = global.workspace_manager.get_active_workspace();
         let windows = global.display.get_tab_list(Meta.TabList.NORMAL, workspace);

extensions/windowsNavigator/extension.js

@@ -158,7 +158,7 @@ var MyWorkspacesView = class extends WorkspacesView.WorkspacesView {
     }
 
     _onKeyPress(s, o) {
-        let viewSelector = Main.overview.viewSelector;
+        let { viewSelector } = Main.overview;
         if (viewSelector._activePage != viewSelector._workspacesPage)
             return false;