题解功能

hydro/lib/paginate.js

@@ -0,0 +1,10 @@
+const { ValidationError } = require('../error');
+module.exports = async function paginate(cursor, page, page_size) {
+    if (page <= 0) throw new ValidationError('page');
+    let [count, page_docs] = await Promise.all([
+        cursor.count(),
+        cursor.skip((page - 1) * page_size).limit(page_size).toArray()
+    ]);
+    let num_pages = Math.floor((count + page_size - 1) / page_size);
+    return [page_docs, num_pages, count];
+};