From 21963de63981490fc630bfae41df154773f20166 Mon Sep 17 00:00:00 2001
From: Laura C <laura.csaki.uk@gmail.com>
Date: Sat, 4 Apr 2026 22:13:00 +0100
Subject: [PATCH 1/4] Fix book rendering on page load

---
 debugging/book-library/script.js | 106 ++++++++++++++++---------------
 1 file changed, 54 insertions(+), 52 deletions(-)

diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
index 75ce6c1d..020d6ded 100644
--- a/debugging/book-library/script.js
+++ b/debugging/book-library/script.js
@@ -1,14 +1,23 @@
+class Book {
+  constructor(title, author, pages, check) {
+    this.title = title.trim();
+    this.author = author.trim();
+    this.pages = Number(pages);
+    this.check = check;
+  }
+}
+
 let myLibrary = [];
 
-window.addEventListener("load", function (e) {
+window.addEventListener("load", function () {
   populateStorage();
   render();
 });
 
 function populateStorage() {
-  if (myLibrary.length == 0) {
-    let book1 = new Book("Robison Crusoe", "Daniel Defoe", "252", true);
-    let book2 = new Book(
+  if (myLibrary.length === 0) {
+    const book1 = new Book("Robinson Crusoe", "Daniel Defoe", "252", true);
+    const book2 = new Book(
       "The Old Man and the Sea",
       "Ernest Hemingway",
       "127",
@@ -16,7 +25,6 @@ function populateStorage() {
     );
     myLibrary.push(book1);
     myLibrary.push(book2);
-    render();
   }
 }
 
@@ -25,78 +33,72 @@ const author = document.getElementById("author");
 const pages = document.getElementById("pages");
 const check = document.getElementById("check");
 
-//check the right input from forms and if its ok -> add the new book (object in array)
-//via Book function and start render function
 function submit() {
   if (
-    title.value == null ||
-    title.value == "" ||
-    pages.value == null ||
-    pages.value == ""
+    title.value.trim() === "" ||
+    author.value.trim() === "" ||
+    pages.value === ""
   ) {
     alert("Please fill all fields!");
     return false;
   } else {
-    let book = new Book(title.value, title.value, pages.value, check.checked);
-    library.push(book);
+    const book = new Book(
+      title.value,
+      author.value,
+      pages.value,
+      check.checked
+    );
+    myLibrary.push(book);
     render();
-  }
-}
 
-function Book(title, author, pages, check) {
-  this.title = title;
-  this.author = author;
-  this.pages = pages;
-  this.check = check;
+    title.value = "";
+    author.value = "";
+    pages.value = "";
+    check.checked = false;
+  }
 }
 
 function render() {
-  let table = document.getElementById("display");
-  let rowsNumber = table.rows.length;
-  //delete old table
-  for (let n = rowsNumber - 1; n > 0; n-- {
+  const table = document.getElementById("display");
+  const rowsNumber = table.rows.length;
+
+  for (let n = rowsNumber - 1; n > 0; n--) {
     table.deleteRow(n);
   }
-  //insert updated row and cells
-  let length = myLibrary.length;
-  for (let i = 0; i < length; i++) {
-    let row = table.insertRow(1);
-    let titleCell = row.insertCell(0);
-    let authorCell = row.insertCell(1);
-    let pagesCell = row.insertCell(2);
-    let wasReadCell = row.insertCell(3);
-    let deleteCell = row.insertCell(4);
+
+  for (let i = 0; i < myLibrary.length; i++) {
+    const row = table.insertRow(1);
+    const titleCell = row.insertCell(0);
+    const authorCell = row.insertCell(1);
+    const pagesCell = row.insertCell(2);
+    const wasReadCell = row.insertCell(3);
+    const deleteCell = row.insertCell(4);
+
     titleCell.innerHTML = myLibrary[i].title;
     authorCell.innerHTML = myLibrary[i].author;
     pagesCell.innerHTML = myLibrary[i].pages;
 
-    //add and wait for action for read/unread button
-    let changeBut = document.createElement("button");
-    changeBut.id = i;
+    const changeBut = document.createElement("button");
     changeBut.className = "btn btn-success";
+    changeBut.innerText = myLibrary[i].check ? "Yes" : "No";
     wasReadCell.appendChild(changeBut);
-    let readStatus = "";
-    if (myLibrary[i].check == false) {
-      readStatus = "Yes";
-    } else {
-      readStatus = "No";
-    }
-    changeBut.innerText = readStatus;
 
     changeBut.addEventListener("click", function () {
       myLibrary[i].check = !myLibrary[i].check;
       render();
     });
 
-    //add delete button to every row and render again
-    let delButton = document.createElement("button");
-    delBut.id = i + 5;
-    deleteCell.appendChild(delBut);
-    delBut.className = "btn btn-warning";
-    delBut.innerHTML = "Delete";
-    delBut.addEventListener("clicks", function () {
-      alert(`You've deleted title: ${myLibrary[i].title}`);
-      myLibrary.splice(i, 1);
+    const delButton = document.createElement("button");
+    delButton.id = `delButton_${i}`;
+    delButton.className = "btn btn-warning";
+    delButton.textContent = "Delete";
+    delButton.dataset.index = i;
+    deleteCell.appendChild(delButton);
+
+    delButton.addEventListener("click", function (e) {
+      const index = e.target.dataset.index;
+      alert(`You've deleted title: ${myLibrary[index].title}`);
+      myLibrary.splice(index, 1);
       render();
     });
   }

From c11fdb4f1517e14ddfd9830803d100965a55dd25 Mon Sep 17 00:00:00 2001
From: Laura C <laura.csaki.uk@gmail.com>
Date: Sat, 4 Apr 2026 22:31:41 +0100
Subject: [PATCH 2/4] Improve validation to prevent invalid page numbers

---
 debugging/book-library/script.js | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
index 020d6ded..0e0ac5be 100644
--- a/debugging/book-library/script.js
+++ b/debugging/book-library/script.js
@@ -34,11 +34,12 @@ const pages = document.getElementById("pages");
 const check = document.getElementById("check");
 
 function submit() {
-  if (
-    title.value.trim() === "" ||
-    author.value.trim() === "" ||
-    pages.value === ""
-  ) {
+ if (
+  title.value.trim() === "" ||
+  author.value.trim() === "" ||
+  pages.value === "" ||
+  Number(pages.value) <= 0
+) {
     alert("Please fill all fields!");
     return false;
   } else {

From dac8c46be97178e6d0bb523fa707ccc2a61fff6b Mon Sep 17 00:00:00 2001
From: Laura C <laura.csaki.uk@gmail.com>
Date: Tue, 7 Apr 2026 22:46:22 +0100
Subject: [PATCH 3/4] Refactor code: improve validation, naming, and DOM
 handling based on review feedback

---
 debugging/book-library/script.js | 96 +++++++++++++++++---------------
 1 file changed, 51 insertions(+), 45 deletions(-)

diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
index 0e0ac5be..ddb735c2 100644
--- a/debugging/book-library/script.js
+++ b/debugging/book-library/script.js
@@ -16,11 +16,11 @@ window.addEventListener("load", function () {
 
 function populateStorage() {
   if (myLibrary.length === 0) {
-    const book1 = new Book("Robinson Crusoe", "Daniel Defoe", "252", true);
+    const book1 = new Book("Robinson Crusoe", "Daniel Defoe", 252, true);
     const book2 = new Book(
       "The Old Man and the Sea",
       "Ernest Hemingway",
-      "127",
+      127,
       true
     );
     myLibrary.push(book1);
@@ -28,35 +28,40 @@ function populateStorage() {
   }
 }
 
-const title = document.getElementById("title");
-const author = document.getElementById("author");
-const pages = document.getElementById("pages");
-const check = document.getElementById("check");
+const titleInput = document.getElementById("title");
+const authorInput = document.getElementById("author");
+const pagesInput = document.getElementById("pages");
+const readCheckbox = document.getElementById("check");
 
 function submit() {
- if (
-  title.value.trim() === "" ||
-  author.value.trim() === "" ||
-  pages.value === "" ||
-  Number(pages.value) <= 0
-) {
-    alert("Please fill all fields!");
-    return false;
-  } else {
-    const book = new Book(
-      title.value,
-      author.value,
-      pages.value,
-      check.checked
-    );
-    myLibrary.push(book);
-    render();
+  const titleValue = titleInput.value.trim();
+  const authorValue = authorInput.value.trim();
+  const pagesValue = Number(pagesInput.value);
 
-    title.value = "";
-    author.value = "";
-    pages.value = "";
-    check.checked = false;
+  if (
+    titleValue === "" ||
+    authorValue === "" ||
+    !Number.isInteger(pagesValue) ||
+    pagesValue <= 0
+  ) {
+    alert("Please fill all fields and enter a whole page count greater than 0.");
+    return false;
   }
+
+  const book = new Book(
+    titleValue,
+    authorValue,
+    pagesValue,
+    readCheckbox.checked
+  );
+
+  myLibrary.push(book);
+  render();
+
+  titleInput.value = "";
+  authorInput.value = "";
+  pagesInput.value = "";
+  readCheckbox.checked = false;
 }
 
 function render() {
@@ -75,32 +80,33 @@ function render() {
     const wasReadCell = row.insertCell(3);
     const deleteCell = row.insertCell(4);
 
-    titleCell.innerHTML = myLibrary[i].title;
-    authorCell.innerHTML = myLibrary[i].author;
-    pagesCell.innerHTML = myLibrary[i].pages;
+    titleCell.textContent = myLibrary[i].title;
+    authorCell.textContent = myLibrary[i].author;
+    pagesCell.textContent = myLibrary[i].pages;
 
-    const changeBut = document.createElement("button");
-    changeBut.className = "btn btn-success";
-    changeBut.innerText = myLibrary[i].check ? "Yes" : "No";
-    wasReadCell.appendChild(changeBut);
+    const toggleReadButton = document.createElement("button");
+    toggleReadButton.className = "btn btn-success";
+    toggleReadButton.textContent = myLibrary[i].check ? "Yes" : "No";
+    wasReadCell.appendChild(toggleReadButton);
 
-    changeBut.addEventListener("click", function () {
+    toggleReadButton.addEventListener("click", function () {
       myLibrary[i].check = !myLibrary[i].check;
       render();
     });
 
-    const delButton = document.createElement("button");
-    delButton.id = `delButton_${i}`;
-    delButton.className = "btn btn-warning";
-    delButton.textContent = "Delete";
-    delButton.dataset.index = i;
-    deleteCell.appendChild(delButton);
+    const deleteButton = document.createElement("button");
+    deleteButton.className = "btn btn-warning";
+    deleteButton.textContent = "Delete";
+    deleteButton.dataset.index = i;
+    deleteCell.appendChild(deleteButton);
+
+    deleteButton.addEventListener("click", function (e) {
+      const index = Number(e.target.dataset.index);
+      const deletedTitle = myLibrary[index].title;
 
-    delButton.addEventListener("click", function (e) {
-      const index = e.target.dataset.index;
-      alert(`You've deleted title: ${myLibrary[index].title}`);
       myLibrary.splice(index, 1);
       render();
+      alert(`You've deleted title: ${deletedTitle}`);
     });
   }
-}
+}
\ No newline at end of file

From d4617895ae5c60130077ae92e920d7a5947ceffd Mon Sep 17 00:00:00 2001
From: Laura C <laura.csaki.uk@gmail.com>
Date: Tue, 7 Apr 2026 22:48:04 +0100
Subject: [PATCH 4/4] Update HTML: load script as module

---
 debugging/book-library/index.html | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/debugging/book-library/index.html b/debugging/book-library/index.html
index 23acfa71..5cdc7b00 100644
--- a/debugging/book-library/index.html
+++ b/debugging/book-library/index.html
@@ -91,6 +91,6 @@ <h1>Library</h1>
       </tbody>
     </table>
 
-    <script src="script.js"></script>
+    <script src="script.js" type="module"></script>
   </body>
 </html>