Fix

dist/ngx-flowchart/bundles/ngx-flowchart.umd.js

@@ -418,13 +418,26 @@
      * @record
      */
     function FcAdjacentList() { }
+    var BaseError = /** @class */ (function () {
+        function BaseError() {
+            Error.apply(this, arguments);
+        }
+        return BaseError;
+    }());
+    BaseError.prototype = new Error();
     var ModelvalidationError = /** @class */ (function (_super) {
         __extends(ModelvalidationError, _super);
         function ModelvalidationError(message) {
-            return _super.call(this, message) || this;
+            var _this = _super.call(this) || this;
+            _this.message = message;
+            return _this;
         }
         return ModelvalidationError;
-    }(Error));
+    }(BaseError));
+    if (false) {
+        /** @type {?} */
+        ModelvalidationError.prototype.message;
+    }
     /**
      * @param {?} graph
      * @return {?}

dist/ngx-flowchart/fesm2015/ngx-flowchart.js

@@ -219,14 +219,25 @@ if (false) {
  * @record
  */
 function FcAdjacentList() { }
-class ModelvalidationError extends Error {
+class BaseError {
+    constructor() {
+        Error.apply(this, arguments);
+    }
+}
+BaseError.prototype = new Error();
+class ModelvalidationError extends BaseError {
     /**
      * @param {?} message
      */
     constructor(message) {
-        super(message);
+        super();
+        this.message = message;
     }
 }
+if (false) {
+    /** @type {?} */
+    ModelvalidationError.prototype.message;
+}
 /**
  * @param {?} graph
  * @return {?}

dist/ngx-flowchart/fesm5/ngx-flowchart.js

@@ -220,13 +220,26 @@ if (false) {
  * @record
  */
 function FcAdjacentList() { }
+var BaseError = /** @class */ (function () {
+    function BaseError() {
+        Error.apply(this, arguments);
+    }
+    return BaseError;
+}());
+BaseError.prototype = new Error();
 var ModelvalidationError = /** @class */ (function (_super) {
     __extends(ModelvalidationError, _super);
     function ModelvalidationError(message) {
-        return _super.call(this, message) || this;
+        var _this = _super.call(this) || this;
+        _this.message = message;
+        return _this;
     }
     return ModelvalidationError;
-}(Error));
+}(BaseError));
+if (false) {
+    /** @type {?} */
+    ModelvalidationError.prototype.message;
+}
 /**
  * @param {?} graph
  * @return {?}

dist/ngx-flowchart/lib/ngx-flowchart.models.d.ts

@@ -109,7 +109,12 @@ export interface FcAdjacentList {
         outgoing: Array<string>;
     };
 }
-export declare class ModelvalidationError extends Error {
+declare class BaseError {
+    constructor();
+}
+export declare class ModelvalidationError extends BaseError {
+    message: string;
     constructor(message: string);
 }
 export declare function fcTopSort(graph: FcModel): Array<string> | null;
+export {};

projects/ngx-flowchart/src/lib/ngx-flowchart.models.ts

@@ -130,9 +130,17 @@ export interface FcAdjacentList {
   };
 }
 
-export class ModelvalidationError extends Error {
-  constructor(message: string) {
-    super(message);
+class BaseError {
+  constructor() {
+    Error.apply(this, arguments);
+  }
+}
+
+BaseError.prototype = new Error();
+
+export class ModelvalidationError extends BaseError {
+  constructor(public message: string) {
+    super();
   }
 }