From 6cac8f1f9a4e3c8fd63df30710c93fe4099a3563 Mon Sep 17 00:00:00 2001
From: Roger Heathcote <git@technicalbloke.com>
Date: Sat, 18 Apr 2020 15:19:55 +0100
Subject: [PATCH] Refactored update function with SQL COALESCE keyword and
 added some comments.

Relates #53

Co-authored-by: tacotoemeck <wagner.tomek@gmail.com>
Co-authored-by: Roger-Heathcote <github@technicalbloke.com>
Co-authored-by: Chloeh24 <chloeh24@hotmail.com>
Co-authored-by: Alexreid95 <alexreid95@gmail.com>
---
 handlers/users.js   |  4 +++-
 model/examples.js   | 52 ++++++++++++++-------------------------------
 tests/model.test.js |  5 +----
 3 files changed, 20 insertions(+), 41 deletions(-)

diff --git a/handlers/users.js b/handlers/users.js
index b2f09fe..74de171 100644
--- a/handlers/users.js
+++ b/handlers/users.js
@@ -49,7 +49,9 @@ function signup(req, res, next) {
     })
     .catch(console.error);
 }
-
+// login function 
+// IMPROVEMENTS 
+// display error message if email or password are missing
 function login(req, res, next) {
   model
     .getUser(req.body.email)
diff --git a/model/examples.js b/model/examples.js
index 6101c09..3ad6a35 100644
--- a/model/examples.js
+++ b/model/examples.js
@@ -61,47 +61,13 @@ function getExample(id) {
     .then((res) => res.rows[0]);
 }
 
- //must update ALL VALUES otherwise any value not updated will return NULL
-
-// function updateExample(id, newdata) {
-//   return (
-//     db
-//       .query(
-//         "UPDATE examples SET language=($1), title=($2), example=($3) WHERE id =($4) RETURNING  *",
-//         [newdata.language, newdata.title, newdata.example, id]
-//       )
-//      
-//       .then((res) => res.rows[0])
-//   );
-
-// }
 
 function updateExamplebyID(id, newdata, userId) {
     return getExample(id)
     .then(dbExample => {
     if(dbExample.id === userId){
-
-        var query = ["UPDATE examples"];
-        query.push("SET");
-      
-        // Create new array and store each set parameter
-        // assign a number value for parameterized query
-        const set = [];
-        const values = [];
-        Object.keys(newdata).forEach((key, i) => {
-          set.push(key + "=($" + (i + 1) + ")");
-          values.push(newdata[key]);
-        });
-        query.push(set.join(", "));
-      
-        // Add WHERE statement to look up by id
-        query.push("WHERE id=" + id + " RETURNING *");
-       
-        // Return a complete query string
-      //   console.log(query.join(" "))
-      //   console.log(values)
-      
-        return db.query(query.join(" "), values)
+      const vals = [ newdata.language, newdata.title, newdata.example, id ];
+      return db.query("UPDATE examples SET language = COALESCE($1, language), title = COALESCE($2, title), example = COALESCE($3, example) WHERE id =($4) RETURNING *", vals)
         .then((res) => res.rows[0]);
       } else {
         const error = new Error("You do not own this example")
@@ -110,7 +76,21 @@ function updateExamplebyID(id, newdata, userId) {
     }
  })
 }
+
+// var query = ["UPDATE examples"];
+//         query.push("SET");
   
+//         const set = [];
+//         const values = [];
+//         Object.keys(newdata).forEach((key, i) => {
+//           set.push(key + "=($" + (i + 1) + ")");
+//           values.push(newdata[key]);
+//         });
+//         query.push(set.join(", "));
+    
+//         query.push("WHERE id=" + id + " RETURNING *");
+      
+//         return db.query(query.join(" "), values)
 
 module.exports = {
   getAllExamples,
diff --git a/tests/model.test.js b/tests/model.test.js
index 68ae6cb..6a30e31 100644
--- a/tests/model.test.js
+++ b/tests/model.test.js
@@ -12,7 +12,6 @@ const {
 
 const {
   getExample,
-  // updateExample,
   updateExamplebyID
 } = require("../model/examples");
 
@@ -76,17 +75,15 @@ test("Can get an example by id", (t) => {
 });
 
 
-test("Can get update an example by id without all values", (t) => {
+test.only("Can get update an example by id without all values", (t) => {
   build().then(() => {
     const data = {
       language: "sql",
-      // title: 'SQL example snippet',
       example: "This is an example of SQL",
     };
     updateExamplebyID(4, data, 4)
       .then((res) => {
         t.equal(res.language, "sql", "Language updated OK");
-        // t.equal(res.title, 'SQL example snippet')
         t.equal(res.title, "Test example 4", "Title not altered");
         t.equal(res.example, "This is an example of SQL", "Example text updated OK");
         t.end();