chore: add default handlers for subscribe (#357)

Adds default handlers for TopicClient.subscribe.
momentohq · Mar 21, 2023 · 81ba86a · 81ba86a
1 parent 20361f4
commit 81ba86a
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Showing 3 changed files with 33 additions and 15 deletions.
diff --git a/src/internal/pubsub-client.ts b/src/internal/pubsub-client.ts
@@ -176,13 +176,25 @@ export class PubsubClient {
       truncateString(topicName)
     );
 
+    const onItem =
+      options.onItem ??
+      (() => {
+        return;
+      });
+    const onError =
+      options.onError ??
+      (() => {
+        return;
+      });
+
     return await new Promise(resolve => {
       const subscriptionState = new SubscriptionState();
       const subscription = new TopicSubscribe.Subscription(subscriptionState);
       this.sendSubscribe(
         cacheName,
         topicName,
-        options,
+        onItem,
+        onError,
         subscriptionState,
         subscription
       );
@@ -210,7 +222,11 @@ export class PubsubClient {
   private sendSubscribe(
     cacheName: string,
     topicName: string,
-    options: SubscribeCallOptions,
+    onItem: (item: TopicSubscribe.Item) => void,
+    onError: (
+      error: TopicSubscribe.Error,
+      subscription: TopicSubscribe.Subscription
+    ) => void,
     subscriptionState: SubscriptionState,
     subscription: TopicSubscribe.Subscription
   ): void {
@@ -244,15 +260,15 @@ export class PubsubClient {
           subscriptionState.lastTopicSequenceNumber =
             resp.item.topic_sequence_number;
           if (resp.item.value.text) {
-            options.onItem(new TopicSubscribe.Item(resp.item.value.text));
+            onItem(new TopicSubscribe.Item(resp.item.value.text));
           } else if (resp.item.value.binary) {
-            options.onItem(new TopicSubscribe.Item(resp.item.value.binary));
+            onItem(new TopicSubscribe.Item(resp.item.value.binary));
           } else {
             this.logger.error(
               'Received subscription item with unknown type; topic: %s',
               truncateString(topicName)
             );
-            options.onError(
+            onError(
               new TopicSubscribe.Error(
                 new UnknownError('Unknown item value type')
               ),
@@ -274,7 +290,7 @@ export class PubsubClient {
             'Received unknown subscription item; topic: %s',
             truncateString(topicName)
           );
-          options.onError(
+          onError(
             new TopicSubscribe.Error(new UnknownError('Unknown item type')),
             subscription
           );
@@ -298,7 +314,8 @@ export class PubsubClient {
           this.sendSubscribe(
             cacheName,
             topicName,
-            options,
+            onItem,
+            onError,
             subscriptionState,
             subscription
           );
@@ -307,7 +324,7 @@ export class PubsubClient {
         }
 
         // Otherwise we propagate the error to the caller.
-        options.onError(
+        onError(
           new TopicSubscribe.Error(cacheServiceErrorMapper(serviceError)),
           subscription
         );
@@ -334,7 +351,8 @@ export class PubsubClient {
         this.sendSubscribe(
           cacheName,
           topicName,
-          options,
+          onItem,
+          onError,
           subscriptionState,
           subscription
         );

diff --git a/src/topic-client.ts b/src/topic-client.ts
@@ -45,9 +45,9 @@ export class TopicClient {
    *
    * @param {string} cacheName - The name of the cache to containing the topic to subscribe to.
    * @param {string} topicName - The name of the topic to subscribe to.
-   * @param {SubscribeCallOptions} options - The options for the subscription.
-   * @param {function} options.onItem - The callback to invoke when data is received.
-   * @param {function} options.onError - The callback to invoke when an error is received.
+   * @param {SubscribeCallOptions} options - The options for the subscription. Defaults to no-op handlers.
+   * @param {function} options.onItem - The callback to invoke when data is received. Defaults to no-op.
+   * @param {function} options.onError - The callback to invoke when an error is received. Defaults to no-op.
    * @returns {Promise<TopicSubscribe.Response>} -
    * {@link TopicSubscribe.Subscription} on success.
    * {@link TopicSubscribe.Error} on failure.

diff --git a/src/utils/topic-call-options.ts b/src/utils/topic-call-options.ts
@@ -9,16 +9,16 @@ export interface SubscribeCallOptions {
    *
    * @param data The data received from the topic subscription.
    */
-  onItem(data: TopicSubscribe.Item): void;
+  onItem?: (data: TopicSubscribe.Item) => void;
 
   /**
    * The callback to invoke when an error is received from the topic subscription.
    *
    * @param error The error received from the topic subscription.
    * @param subscription The subscription that received the error.
    */
-  onError(
+  onError?: (
     error: TopicSubscribe.Error,
     subscription: TopicSubscribe.Subscription
-  ): void;
+  ) => void;
 }