feat: similar products

pages/api/product/[productId].js

 const Product = require('../../../models/product');
 import dbConnect from '../../../utils/helpers/dbHelpers';
 
+const shuffle = function (v) {
+  //+ Jonas Raoni Soares Silva
+  //@ http://jsfromhell.com/array/shuffle [rev. #1]
+
+  for (
+    var j, x, i = v.length;
+    i;
+    j = parseInt(Math.random() * i), x = v[--i], v[i] = v[j], v[j] = x
+  );
+  return v;
+};
+
 async function handler(req, res) {
   const { method } = req;
 
           throw new Error('The product with this id does not exist!');
         }
 
+        const similarProducts = await Product.find({
+          category: product.category,
+          customID: { $ne: product.customID },
+        });
+
+        const shuffled = similarProducts
+          .sort(() => 0.5 - Math.random())
+          .slice(0, 3);
+
         res.status(200).json({
           message: 'The product you requested was fetched successfully.',
           product,
+          similarProducts: shuffled,
         });
       } catch (error) {
         res.status(400).json({ message: error.message });