♻️ Improve error messages (#22)

Author: spontoreau

src/core/errors/multipleHandlers.error.ts

@@ -0,0 +1,7 @@
+export class MultipleHandlersError extends Error {
+  constructor(messageType: string) {
+    super(
+      `Multiple handlers are registred, use publish function instead (MESSAGE_TYPE: ${messageType})`,
+    );
+  }
+}

src/core/errors/multipleHandlersMessage.error.ts

@@ -1,5 +1,7 @@
 export class UnknownMessageError extends Error {
-  constructor() {
-    super(`The message doesn't have any corresponding handler`);
+  constructor(messageType: string) {
+    super(
+      `The message doesn't have any corresponding handler (MESSAGE_TYPE: ${messageType})`,
+    );
   }
 }

src/core/errors/unknownMessage.error.ts

@@ -4,7 +4,7 @@ import { Message } from './message';
 import { MessageHandler } from './messageHandler';
 import { clear, mediator } from './mediator';
 import { UnknownMessageError } from './errors/unknownMessage.error';
-import { SendToMultipleHandlersError } from './errors/multipleHandlersMessage.error';
+import { MultipleHandlersError } from './errors/multipleHandlers.error';
 import { should } from 'chai';
 import { Middleware } from './middlewares';
 
@@ -87,6 +87,9 @@ describe('mediator.send', () => {
 
     // Assert
     actual.should.be.instanceOf(UnknownMessageError);
+    actual.message.should.be.equal(
+      `The message doesn't have any corresponding handler (MESSAGE_TYPE: CREATE_PERSON)`,
+    );
   });
 
   it('should throw error when sending a message through the mediator that can be handled with multiple handlers', async () => {
@@ -126,7 +129,10 @@ describe('mediator.send', () => {
     }
 
     // Assert
-    actual.should.be.instanceOf(SendToMultipleHandlersError);
+    actual.should.be.instanceOf(MultipleHandlersError);
+    actual.message.should.be.equal(
+      `Multiple handlers are registred, use publish function instead (MESSAGE_TYPE: CREATE_PERSON)`,
+    );
   });
 });
 
@@ -213,6 +219,9 @@ describe('mediator.publish', () => {
 
     // Assert
     actual.should.be.instanceOf(UnknownMessageError);
+    actual.message.should.be.equal(
+      `The message doesn't have any corresponding handler (MESSAGE_TYPE: CREATE_PERSON)`,
+    );
   });
 });
 

src/core/mediator.test.ts

@@ -1,7 +1,7 @@
 import { Message } from './message';
 import { MessageHandler } from './messageHandler';
 import { MessageResult } from './messageResult';
-import { SendToMultipleHandlersError } from './errors/multipleHandlersMessage.error';
+import { MultipleHandlersError } from './errors/multipleHandlers.error';
 import { UnknownMessageError } from './errors/unknownMessage.error';
 import { AddOptions, Middleware, middlewares } from './middlewares';
 
@@ -19,7 +19,7 @@ const getHandlers = <TKey extends string, TMessage extends Message<TKey>>(
   messageType: TKey,
 ): Array<MessageHandler<TMessage>> => {
   if (!registry.has(messageType)) {
-    throw new UnknownMessageError();
+    throw new UnknownMessageError(messageType);
   }
 
   const handlers = registry.get(messageType) as Array<MessageHandler<TMessage>>;
@@ -33,7 +33,7 @@ const send = async <TMessage extends Message>({
   const handlers = getHandlers<typeof type, TMessage>(type);
 
   if (handlers.length > 1) {
-    throw new SendToMultipleHandlersError();
+    throw new MultipleHandlersError(type);
   }
 
   return handlers[0](data);