Implemented findOneAndUpdate middleware

Author: Farhan Hasin Chowdhury

lib/simple-slugify.js

@@ -29,4 +29,27 @@ module.exports = function (schema) {
 
     next();
   });
+
+  schema.pre(['findOneAndUpdate'], async function (next) {
+    const regex = /[&/\\#,+()$~%.'":*?<>{} ]/g;
+
+    let slug = this.get(this.schema.tree.slug.source)
+      .toString()
+      .toLowerCase()
+      .trim()
+      .replace(regex, '-');
+
+    try {
+      slug = (await this.model.exists({ slug }))
+        ? `${slug}-${crypto.randomBytes(5).toString('hex')}`
+        : slug;
+    } catch (error) {
+      // eslint-disable-next-line no-console
+      console.log(error);
+    }
+
+    this.set({ slug });
+
+    next();
+  });
 };