CodeYourFuture · RaihanSharif · Mar 6, 2026 · Mar 6, 2026 · Mar 6, 2026 · Mar 6, 2026
diff --git a/debugging/book-library/index.html b/debugging/book-library/index.html
@@ -1,20 +1,18 @@
-<!DOCTYPE html>
-<html>
+<!doctype html>
+<html lang="en">
   <head>
-    <title> </title>
-    <meta
-      charset="utf-8"
-      name="viewport"
-      content="width=device-width, initial-scale=1.0"
-    />
+    <title>Book library app</title>
     <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.4.1/jquery.min.js"></script>
     <script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.16.0/umd/popper.min.js"></script>
     <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/js/bootstrap.min.js"></script>
     <link
       rel="stylesheet"
       href="https://maxcdn.bootstrapcdn.com/bootstrap/4.4.1/css/bootstrap.min.css"
     />
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
     <link rel="stylesheet" type="text/css" href="style.css" />
+    <script type="module" src="script.js"></script>
   </head>
 
   <body>
@@ -29,20 +27,24 @@ <h1>Library</h1>
 
     <div id="demo" class="collapse">
       <div class="form-group">
-        <label for="title">Title:</label>
+        <label for="book-title">Title:</label>
         <input
-          type="title"
+          type="text"
           class="form-control"
-          id="title"
-          name="title"
+          id="book-title"
+          name="book-title"
+          minlength="1"
+          maxlength="255"
           required
         />
         <label for="author">Author: </label>
         <input
-          type="author"
+          type="text"
           class="form-control"
           id="author"
           name="author"
+          minlength="1"
+          maxlength="255"
           required
         />
         <label for="pages">Pages:</label>
@@ -51,6 +53,8 @@ <h1>Library</h1>
           class="form-control"
           id="pages"
           name="pages"
+          min="1"
+          max="10000"
           required
         />
         <label class="form-check-label">
@@ -59,13 +63,13 @@ <h1>Library</h1>
             class="form-check-input"
             id="check"
             value=""
-          />Read
+          />completed
         </label>
         <input
           type="submit"
           value="Submit"
           class="btn btn-primary"
-          onclick="submit();"
+          id="submit-btn"
         />
       </div>
     </div>
@@ -76,7 +80,7 @@ <h1>Library</h1>
           <th>Title</th>
           <th>Author</th>
           <th>Number of Pages</th>
-          <th>Read</th>
+          <th>Completed</th>
           <th></th>
         </tr>
       </thead>
@@ -90,7 +94,5 @@ <h1>Library</h1>
         </tr>
       </tbody>
     </table>
-
-    <script src="script.js"></script>
   </body>
 </html>
diff --git a/debugging/book-library/script.js b/debugging/book-library/script.js
@@ -1,101 +1,125 @@
-let myLibrary = [];
+const myLibrary = [];
 
 window.addEventListener("load", function (e) {
   populateStorage();
-  render();
 });
 
 function populateStorage() {
   if (myLibrary.length == 0) {
-    let book1 = new Book("Robison Crusoe", "Daniel Defoe", "252", true);
-    let book2 = new Book(
+    const book1 = new Book("Robison Crusoe", "Daniel Defoe", "252", true);
+    const book2 = new Book(
       "The Old Man and the Sea",
       "Ernest Hemingway",
       "127",
       true
     );
+
     myLibrary.push(book1);
     myLibrary.push(book2);
     render();
   }
 }
 
-const title = document.getElementById("title");
-const author = document.getElementById("author");
-const pages = document.getElementById("pages");
-const check = document.getElementById("check");
+const titleInput = document.getElementById("book-title");
+const authorInput = document.getElementById("author");
+const pagesInput = document.getElementById("pages");
+const isReadCheckbox = document.getElementById("check");
+const submitBtn = document.getElementById("submit-btn");
 
 //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 == ""
-  ) {
-    alert("Please fill all fields!");
+  const title = titleInput.value.trim();
+  const author = authorInput.value.trim();
+  const pages = Number(pagesInput.value);
+
+  if (title === "") {
+    alert("Please fill title field!");
+    return false;
+  }
+
+  if (!Number.isInteger(pages) || pages < 1) {
+    alert("Pages must be a whole number greater than 0!");
     return false;
-  } else {
-    let book = new Book(title.value, title.value, pages.value, check.checked);
-    library.push(book);
-    render();
   }
+
+  const book = new Book(title, author, pages, isReadCheckbox.checked);
+
+  if (isBookInLibrary(book)) {
+    alert("This book is already in the library!");
+    return false;
+  }
+  myLibrary.push(book);
+  resetInputFields();
+  render();
+}
+
+submitBtn.addEventListener("click", submit);
+
+function isBookInLibrary(newBook) {
+  return myLibrary.some(
+    (old) =>
+      old.title.toLowerCase() === newBook.title.toLowerCase() &&
+      old.author.toLowerCase() === newBook.author.toLowerCase()
+  );
 }
 
-function Book(title, author, pages, check) {
+function resetInputFields() {
+  titleInput.value = "";
+  authorInput.value = "";
+  pagesInput.value = "";
+  isReadCheckbox.checked = false;
+}
+
+function Book(title, author, pages, completed) {
   this.title = title;
   this.author = author;
   this.pages = pages;
-  this.check = check;
+  this.completed = completed;
 }
 
 function render() {
-  let table = document.getElementById("display");
-  let rowsNumber = table.rows.length;
+  const table = document.getElementById("display");
+  const rowsNumber = table.rows.length;
   //delete old table
-  for (let n = rowsNumber - 1; n > 0; n-- {
+  for (let n = rowsNumber - 1; n > 0; n--) {
     table.deleteRow(n);
   }
   //insert updated row and cells
-  let length = myLibrary.length;
+  const 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);
-    titleCell.innerHTML = myLibrary[i].title;
-    authorCell.innerHTML = myLibrary[i].author;
-    pagesCell.innerHTML = myLibrary[i].pages;
+    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.textContent = myLibrary[i].title;
+    authorCell.textContent = myLibrary[i].author;
+    pagesCell.textContent = myLibrary[i].pages;
 
     //add and wait for action for read/unread button
-    let changeBut = document.createElement("button");
-    changeBut.id = i;
-    changeBut.className = "btn btn-success";
-    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;
+    const changeCompletedBtn = document.createElement("button");
+    changeCompletedBtn.className = "btn";
+    wasReadCell.appendChild(changeCompletedBtn);
+    changeCompletedBtn.classList.add(
+      myLibrary[i].completed ? "btn-success" : "btn-secondary"
+    );
+    changeCompletedBtn.textContent = myLibrary[i].completed ? "Yes" : "No";
+
+    changeCompletedBtn.addEventListener("click", function () {
+      myLibrary[i].completed = !myLibrary[i].completed;
       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: ${myLibrary[i].title}`);
+    const delBtn = document.createElement("button");
+    deleteCell.appendChild(delBtn);
+    delBtn.className = "btn btn-warning";
+    delBtn.textContent = "Delete";
+    delBtn.addEventListener("click", function () {
+      const deletedBook = myLibrary[i].title;
+      if (!confirm(`Delete "${deletedBook}?`)) return;
       myLibrary.splice(i, 1);
       render();
     });