Add "allowOverride" option to Jsonthis.registerGlobalSerializer() (#7)

src/jsonthis.test.ts

@@ -48,6 +48,29 @@ describe("Jsonthis class", () => {
             expect(() => jsonthis.registerGlobalSerializer(Date, dateSerializer))
                 .toThrow("Serializer already registered for \"Date\"");
         });
+
+        it("should override a global serializer for a class if the override option is set", () => {
+            function overridingDateSerializer(value: Date): string {
+                return value.toUTCString();
+            }
+
+            class User {
+                public registeredAt: Date = new Date();
+            }
+            const user = new User();
+
+            const jsonthis = new Jsonthis();
+
+            jsonthis.registerGlobalSerializer(Date, dateSerializer);
+            expect(jsonthis.toJson(user)).toStrictEqual({
+                registeredAt: user.registeredAt.toISOString()
+            });
+
+            jsonthis.registerGlobalSerializer(Date, overridingDateSerializer, true);
+            expect(jsonthis.toJson(user)).toStrictEqual({
+                registeredAt: user.registeredAt.toUTCString()
+            });
+        });
     });
 
     describe("toJson method", () => {

src/jsonthis.ts

@@ -62,9 +62,10 @@ export class Jsonthis {
      * Register a global serializer for a class.
      * @param target The class to register the serializer for.
      * @param serializer The serializer function.
+     * @param allowOverride Whether to allow overriding an existing serializer (default is false).
      */
-    registerGlobalSerializer(target: Function, serializer: JsonTraversalFn<any>): void {
-        if (this.serializers.has(target))
+    registerGlobalSerializer(target: Function, serializer: JsonTraversalFn<any>, allowOverride: boolean = false): void {
+        if (this.serializers.has(target) && !allowOverride)
             throw new Error(`Serializer already registered for "${target.name}"`);
         this.serializers.set(target, serializer);
     }