chore: add more comments

lib/filter.ts

@@ -2,10 +2,13 @@ import { UrlConfig } from "./types.d.ts";
 
 export default function filter(headers: Headers, json: any, config: UrlConfig): string | null {
     const event = headers.get("x-github-event") || "unknown";
+
+    // ignore events that Discord won't render anyway
     if (["status", "pull_request_review_thread"].includes(event)) {
         return event;
     }
 
+    // ignore all PR actions except "opened", "closed", "reopened"
     if (
         event === "pull_request" && json.action &&
         !["opened", "closed", "reopened"].includes(json.action)
@@ -13,6 +16,7 @@ export default function filter(headers: Headers, json: any, config: UrlConfig):
         return "no-op PR action";
     }
 
+    // ignore all issue actions except "opened", "deleted", "closed", "reopened", "transferred"
     if (
         event === "issues" && json.action &&
         !["opened", "deleted", "closed", "reopened", "transferred"].includes(json.action)
@@ -20,6 +24,7 @@ export default function filter(headers: Headers, json: any, config: UrlConfig):
         return "no-op issue action";
     }
 
+    // ignore some PR review actions
     if (event === "pull_request_review") {
         // ignore edit/dismiss actions
         if (json.action !== "submitted") return "no-op PR review action";
@@ -27,6 +32,7 @@ export default function filter(headers: Headers, json: any, config: UrlConfig):
         else if (json.review?.state === "commented" && !json.review?.body) return "empty PR review";
     }
 
+    // ignore bots
     const login: string | undefined = json.sender?.login?.toLowerCase();
     if (
         login &&
@@ -35,6 +41,7 @@ export default function filter(headers: Headers, json: any, config: UrlConfig):
         return "bot";
     }
 
+    // ignore branch/tag if configured
     const refMatch = /^refs\/([^\/]+)\/(.+)$/.exec(json.ref);
     if (event === "push" && refMatch) {
         // check if branch is allowed