fix(__extends): Use correct behaviour with null prototype

Author: ExE-Boss

tslib.d.ts

@@ -12,7 +12,7 @@ LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 PERFORMANCE OF THIS SOFTWARE.
 ***************************************************************************** */
-export declare function __extends(d: Function, b: Function): void;
+export declare function __extends(d: Function, b: Function | null): void;
 export declare function __assign(t: any, ...sources: any[]): any;
 export declare function __rest(t: any, propertyNames: (string | symbol)[]): any;
 export declare function __decorate(decorators: Function[], target: any, key?: string | symbol, desc?: any): any;

tslib.es6.js

@@ -22,11 +22,16 @@ var extendStatics = function(d, b) {
 };
 
 export function __extends(d, b) {
-    if (typeof b !== "function" && b !== null)
+    if (b === null) {
+        (d.prototype = Object.create(b)).constructor = d;
+        return;
+    } else if (typeof b !== "function") {
         throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
+    }
     extendStatics(d, b);
     function __() { this.constructor = d; }
-    d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+    __.prototype = b.prototype;
+    d.prototype = new __();
 }
 
 export var __assign = function() {

tslib.js

@@ -66,11 +66,16 @@ var __createBinding;
         function (d, b) { for (var p in b) if (Object.prototype.hasOwnProperty.call(b, p)) d[p] = b[p]; };
 
     __extends = function (d, b) {
-        if (typeof b !== "function" && b !== null)
+        if (b === null) {
+            (d.prototype = Object.create(b)).constructor = d;
+            return;
+        } else if (typeof b !== "function") {
             throw new TypeError("Class extends value " + String(b) + " is not a constructor or null");
+        }
         extendStatics(d, b);
         function __() { this.constructor = d; }
-        d.prototype = b === null ? Object.create(b) : (__.prototype = b.prototype, new __());
+        __.prototype = b.prototype;
+        d.prototype = new __();
     };
 
     __assign = Object.assign || function (t) {