fix: use `isolatedModules: true` in tsconfig.json (#469)

* fix: use `isolatedModules: true` in tsconfig.json

This setting ensures the module can be used in projects where the workflow
includes type checking and transpilation as two separate steps.

See: https://ncjamieson.com/dont-export-const-enums/

Fixes: https://github.com/cloudevents/sdk-javascript/issues/456

Signed-off-by: Lance Ball <lball@redhat.com>

src/index.ts

@@ -17,30 +17,33 @@ import CONSTANTS from "./constants";
 export {
   // From event
   CloudEvent,
-  CloudEventV1,
-  CloudEventV1Attributes,
   Version,
   ValidationError,
+  Mode,
+  HTTP,
+  Kafka,
+  MQTT,
+  MQTTMessageFactory,
+  emitterFor,
+  Emitter,
+  // From Constants
+  CONSTANTS
+};
+
+export type {
+  CloudEventV1,
+  CloudEventV1Attributes,
   // From message
   Headers,
-  Mode,
   Binding,
   Message,
   Deserializer,
   Serializer,
-  HTTP,
-  Kafka,
   KafkaEvent,
   KafkaMessage,
-  MQTT,
   MQTTMessage,
-  MQTTMessageFactory,
   // From transport
   TransportFunction,
   EmitterFunction,
-  emitterFor,
-  Emitter,
-  Options,
-  // From Constants
-  CONSTANTS,
+  Options
 };

src/message/kafka/index.ts

@@ -10,7 +10,10 @@ import { sanitize } from "../http/headers";
 
 // Export the binding implementation and message interface
 export {
-  Kafka,
+  Kafka
+};
+
+export type {
   KafkaMessage,
   KafkaEvent
 };

src/message/mqtt/index.ts

@@ -6,10 +6,9 @@
 import { Binding, Deserializer, CloudEvent, CloudEventV1, CONSTANTS, Message, ValidationError, Headers } from "../..";
 
 export {
-  MQTT,
-  MQTTMessage,
-  MQTTMessageFactory
+  MQTT, MQTTMessageFactory
 };
+export type { MQTTMessage };
 
 /**
  * Extends the base {@linkcode Message} interface to include MQTT attributes, some of which

tsconfig.json

@@ -11,7 +11,8 @@
     "forceConsistentCasingInFileNames": true,  /* Disallow inconsistently-cased references to the same file. */
     "outDir": "./dist",
     "declaration": true,
-    "experimentalDecorators": true
+    "experimentalDecorators": true,
+    "isolatedModules": true,
   },
   "compileOnSave": true,
   "include": [