refactor(js): derive VALID_REACTIONS from REACTION_MAP to remove duplication

- add_reaction_and_edit_comment.cjs: remove hardcoded VALID_REACTIONS array
  and derive it from the exported REACTION_MAP from add_reaction.cjs.
  This eliminates a duplicate list that could drift out of sync.
- add_reaction.cjs: remove transient validReactions local variable;
  validate directly against REACTION_MAP using hasOwnProperty.

Behavior is unchanged — key order is preserved (insertion order matches
the original frozen array), and all 105 JS tests pass.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: github-actions[bot]

actions/setup/js/add_reaction.cjs

@@ -30,9 +30,8 @@ async function main() {
   core.info(`Adding reaction: ${reaction}`);
 
   // Validate reaction type
-  const validReactions = Object.keys(REACTION_MAP);
-  if (!validReactions.includes(reaction)) {
-    core.setFailed(`${ERR_VALIDATION}: Invalid reaction type: ${reaction}. Valid reactions are: ${validReactions.join(", ")}`);
+  if (!Object.prototype.hasOwnProperty.call(REACTION_MAP, reaction)) {
+    core.setFailed(`${ERR_VALIDATION}: Invalid reaction type: ${reaction}. Valid reactions are: ${Object.keys(REACTION_MAP).join(", ")}`);
     return;
   }
 

actions/setup/js/add_reaction_and_edit_comment.cjs

@@ -9,7 +9,7 @@ const { ERR_API, ERR_NOT_FOUND, ERR_VALIDATION } = require("./error_codes.cjs");
 const { buildWorkflowRunUrl } = require("./workflow_metadata_helpers.cjs");
 const { createDiscussionComment, resolveTopLevelDiscussionCommentId } = require("./github_api_helpers.cjs");
 const { resolveInvocationContext } = require("./invocation_context_helpers.cjs");
-const { addReaction, addDiscussionReaction, getDiscussionNodeId } = require("./add_reaction.cjs");
+const { addReaction, addDiscussionReaction, getDiscussionNodeId, REACTION_MAP } = require("./add_reaction.cjs");
 
 /**
  * Event type descriptions for comment messages
@@ -25,7 +25,7 @@ const EVENT_TYPE_DESCRIPTIONS = {
 };
 
 /** Valid GitHub reaction types */
-const VALID_REACTIONS = Object.freeze(["+1", "-1", "laugh", "confused", "heart", "hooray", "rocket", "eyes"]);
+const VALID_REACTIONS = Object.freeze(Object.keys(REACTION_MAP));
 
 /**
  * Resolve the reaction and comment API endpoints for a given event.