js: Check for this.constructor type instead of new.target

Use more ES6-inspired check for classes initializations.

https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/503

js/ui/appDisplay.js

@@ -98,8 +98,8 @@ function clamp(value, min, max) {
 
 class BaseAppView {
     constructor(params, gridParams) {
-        if (new.target === BaseAppView)
+        if (this.constructor === BaseAppView)
-            throw new TypeError('Cannot instantiate abstract class ' + new.target.name);
+            throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
 
         gridParams = Params.parse(gridParams, { xAlign: St.Align.MIDDLE,
                                                 columnLimit: MAX_COLUMNS,

js/ui/popupMenu.js

@@ -397,8 +397,8 @@ var PopupImageMenuItem = class extends PopupBaseMenuItem {
 
 var PopupMenuBase = class {
     constructor(sourceActor, styleClass) {
-        if (new.target === PopupMenuBase)
+        if (this.constructor === PopupMenuBase)
-            throw new TypeError('Cannot instantiate abstract class ' + new.target.name);
+            throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
 
         this.sourceActor = sourceActor;
         this._parent = null;

js/ui/status/keyboard.js

@@ -125,8 +125,8 @@ class InputSourceSwitcher extends SwitcherPopup.SwitcherList {
 
 var InputSourceSettings = class {
     constructor() {
-        if (new.target === InputSourceSettings)
+        if (this.constructor === InputSourceSettings)
-            throw new TypeError('Cannot instantiate abstract class ' + new.target.name);
+            throw new TypeError(`Cannot instantiate abstract class ${this.constructor.name}`);
     }
 
     _emitInputSourcesChanged() {

js/ui/status/network.js

@@ -167,10 +167,10 @@ var NMConnectionItem = class {
 };
 Signals.addSignalMethods(NMConnectionItem.prototype);
 
-var NMConnectionSection = class {
+var NMConnectionSection = class NMConnectionSection {
     constructor(client) {
-        if (new.target === NMConnectionSection)
+        if (this.constructor === NMConnectionSection)
-            throw new TypeError('Cannot instantiate abstract type ' + new.target.name);
+            throw new TypeError(`Cannot instantiate abstract type ${this.constructor.name}`);
 
         this._client = client;
 
@@ -297,12 +297,13 @@ var NMConnectionSection = class {
 };
 Signals.addSignalMethods(NMConnectionSection.prototype);
 
-var NMConnectionDevice = class extends NMConnectionSection {
+var NMConnectionDevice = class NMConnectionDevice extends NMConnectionSection {
     constructor(client, device) {
-        if (new.target === NMConnectionDevice)
-            throw new TypeError('Cannot instantiate abstract type ' + new.target.name);
-
         super(client);
+
+        if (this.constructor === NMConnectionDevice)
+            throw new TypeError(`Cannot instantiate abstract type ${this.constructor.name}`);
+
         this._device = device;
         this._description = '';
 

js/ui/workspace.js

@@ -786,8 +786,8 @@ var WindowPositionFlags = {
 
 var LayoutStrategy = class {
     constructor(monitor, rowSpacing, columnSpacing) {
-        if (new.target === LayoutStrategy)
+        if (this.constructor === LayoutStrategy)
-            throw new TypeError('Cannot instantiate abstract type ' + new.target.name);
+            throw new TypeError(`Cannot instantiate abstract type ${this.constructor.name}`);
 
         this._monitor = monitor;
         this._rowSpacing = rowSpacing;