build: use existing comment for docs preview links (#2169)

build/tasks.ts

@@ -139,17 +139,33 @@ export async function postGithubComment() {
 
     octokit.authenticate({ type: 'token', token });
 
-    const body = `Preview docs changes for ${SHORT_SHA} at https://previews.ngrx.io/pr${PR_NUMBER}-${SHORT_SHA}/`;
-
-    // wait a few seconds for github to settle
-    await util.sleep(5000);
-
-    await octokit.issues.createComment({
+    const comments: { data: any[] } = await octokit.issues.getComments({
       owner,
       repo,
       number: PR_NUMBER,
-      body,
     });
+
+    const ngrxBotComment = comments.data
+      .filter(comment => comment.user.login === 'ngrxbot')
+      .pop();
+
+    const body = `Preview docs changes for ${SHORT_SHA} at https://previews.ngrx.io/pr${PR_NUMBER}-${SHORT_SHA}/`;
+
+    if (ngrxBotComment) {
+      await octokit.issues.editComment({
+        owner,
+        repo,
+        comment_id: ngrxBotComment.id,
+        body,
+      });
+    } else {
+      await octokit.issues.createComment({
+        owner,
+        repo,
+        number: PR_NUMBER,
+        body,
+      });
+    }
   }
 }