rm redundant check, use object build function

src/activity.ts

@@ -177,8 +177,7 @@ export const deleteArticleActivity = (article: Article, user: User) => {
 
 export const createArticleActivity = (article: Article, user: User) => {
     const actor = fillRoute("actor", user.nickname);
-    const published = typeof article.created_at === "number" ? new Date(article.created_at) : article.created_at;
-    const canonicalUrl = `https://${process.env.blog_host}/${article.slug}.html`;
+    const published = article.created_at;
     const context = fillRoute("context", article.id);
     const followers = fillRoute("followers", user.nickname);
     const activity: Record<string, any> = {
@@ -192,29 +191,7 @@ export const createArticleActivity = (article: Article, user: User) => {
         published
     };
 
-    const objectId = fillRoute("object", article.id);
-    const content = readFileSync(article.file as string, "utf-8") + `
-    
-[Read on site](${canonicalUrl})
-            `;
-
-    activity.object = {
-        id: objectId,
-        actor,
-        attributedTo: actor,
-        type: "Note",
-        context,
-        content: md.render(content),
-        to: [PUBLIC],
-        cc: [followers],
-        url: canonicalUrl,
-        mediaType: "text/html",
-        source: {
-            mediaType: "text/markdown",
-            content
-        },
-        published
-    };
+    activity.object = createArticleObject(article, user.nickname);
 
     return activity;
 };
@@ -230,7 +207,7 @@ export const createArticleObject = (article: Article, nickname: string) => {
 [Read on site](${canonicalUrl})
         `;
 
-    const published = typeof article.created_at === "number" ? new Date(article.created_at) : article.created_at;
+    const published = article.created_at;
     
     const followers = fillRoute("followers", nickname);