[code-simplifier] refactor(js): simplify add_reaction.cjs payload validation and error handling

actions/setup/js/add_reaction.cjs

@@ -60,6 +60,21 @@ async function main() {
   }
 }
 
+/**
+ * Extract a required field from the event payload, calling setFailed if missing.
+ * @param {unknown} value - The extracted value (already resolved by caller)
+ * @param {string} fieldName - Human-readable field name for error messages
+ * @param {string} errorCode - Error code prefix (ERR_NOT_FOUND or ERR_VALIDATION)
+ * @returns {boolean} true if valid, false if missing (setFailed already called)
+ */
+function requirePayloadField(value, fieldName, errorCode) {
+  if (value == null) {
+    core.setFailed(`${errorCode}: ${fieldName} not found in event payload`);
+    return false;
+  }
+  return true;
+}
+
 /**
  * Resolve the REST API route and params for non-discussion events.
  * Returns null for discussion/discussion_comment/pull_request_review/unsupported events (handled separately).
@@ -73,38 +88,26 @@ function resolveRestEndpoint(eventName, owner, repo, payload) {
   switch (eventName) {
     case "issues": {
       const issueNumber = payload?.issue?.number;
-      if (!issueNumber) {
-        core.setFailed(`${ERR_NOT_FOUND}: Issue number not found in event payload`);
-        return null;
-      }
+      if (!requirePayloadField(issueNumber, "Issue number", ERR_NOT_FOUND)) return null;
       return { route: "POST /repos/{owner}/{repo}/issues/{issue_number}/reactions", params: { owner, repo, issue_number: issueNumber } };
     }
 
     case "issue_comment": {
       const commentId = payload?.comment?.id;
-      if (!commentId) {
-        core.setFailed(`${ERR_VALIDATION}: Comment ID not found in event payload`);
-        return null;
-      }
+      if (!requirePayloadField(commentId, "Comment ID", ERR_VALIDATION)) return null;
       return { route: "POST /repos/{owner}/{repo}/issues/comments/{comment_id}/reactions", params: { owner, repo, comment_id: commentId } };
     }
 
     case "pull_request": {
       const prNumber = payload?.pull_request?.number;
-      if (!prNumber) {
-        core.setFailed(`${ERR_NOT_FOUND}: Pull request number not found in event payload`);
-        return null;
-      }
+      if (!requirePayloadField(prNumber, "Pull request number", ERR_NOT_FOUND)) return null;
       // PRs are "issues" for the reactions endpoint
       return { route: "POST /repos/{owner}/{repo}/issues/{issue_number}/reactions", params: { owner, repo, issue_number: prNumber } };
     }
 
     case "pull_request_review_comment": {
       const reviewCommentId = payload?.comment?.id;
-      if (!reviewCommentId) {
-        core.setFailed(`${ERR_VALIDATION}: Review comment ID not found in event payload`);
-        return null;
-      }
+      if (!requirePayloadField(reviewCommentId, "Review comment ID", ERR_VALIDATION)) return null;
       return { route: "POST /repos/{owner}/{repo}/pulls/comments/{comment_id}/reactions", params: { owner, repo, comment_id: reviewCommentId } };
     }
 
@@ -134,38 +137,36 @@ function isRestReactionEvent(eventName) {
  * @param {string} reaction
  */
 async function handleGraphQLOrUnknownEvent(eventName, owner, repo, payload, reaction) {
-  switch (eventName) {
-    case "discussion": {
-      const discussionNumber = payload?.discussion?.number;
-      if (!discussionNumber) {
-        core.setFailed(`${ERR_NOT_FOUND}: Discussion number not found in event payload`);
-        return;
+  let subjectId;
+  try {
+    switch (eventName) {
+      case "discussion": {
+        const discussionNumber = payload?.discussion?.number;
+        if (!requirePayloadField(discussionNumber, "Discussion number", ERR_NOT_FOUND)) return;
+        subjectId = await getDiscussionNodeId(owner, repo, discussionNumber);
+        break;
       }
-      try {
-        const discussionNodeId = await getDiscussionNodeId(owner, repo, discussionNumber);
-        await addDiscussionReaction(discussionNodeId, reaction);
-      } catch (error) {
-        handleReactionError(error);
+
+      case "discussion_comment": {
+        const commentNodeId = payload?.comment?.node_id;
+        if (!requirePayloadField(commentNodeId, "Discussion comment node ID", ERR_NOT_FOUND)) return;
+        subjectId = commentNodeId;
+        break;
       }
-      return;
-    }
 
-    case "discussion_comment": {
-      const commentNodeId = payload?.comment?.node_id;
-      if (!commentNodeId) {
-        core.setFailed(`${ERR_NOT_FOUND}: Discussion comment node ID not found in event payload`);
+      default:
+        core.setFailed(`${ERR_VALIDATION}: Unsupported event type: ${eventName}`);
         return;
-      }
-      try {
-        await addDiscussionReaction(commentNodeId, reaction);
-      } catch (error) {
-        handleReactionError(error);
-      }
+    }
+
+    if (subjectId == null) {
+      core.setFailed(`${ERR_VALIDATION}: subjectId could not be resolved for event: ${eventName}`);
       return;
     }
 
-    default:
-      core.setFailed(`${ERR_VALIDATION}: Unsupported event type: ${eventName}`);
+    await addDiscussionReaction(subjectId, reaction);
+  } catch (error) {
+    handleReactionError(error);
   }
 }