featura: excel importer now reads values from all sheets

src/app/components/book/book-excel-parser/book-excel-parser.component.html

@@ -6,25 +6,39 @@ <h1 class="m-2 p-2">Excel importer</h1>
 <div class="container">
   <h2>Instructions</h2>
   <p>
-    1. This importer allows you to choose an excel file, see all the values of it in a table and then import those books into the database.
+    This importer allows you to choose an excel file, see all the values of it in a table and then import those books into the database.
   </p>
   <p>
-    2. Currently <b>supported extensions:</b>.
+    The importer assigns each value of a row depending on the column header. As a consequence the <b>first row of the excel file must contain</b> the following values:
+  </p>
+    <ul>
+      <li><b>Title</b></li>
+      <li><b>ISBN</b></li>
+      <li><b>Active</b></li>
+      <li><b>Price</b></li>
+      <li><b>Stock</b></li>
+      <li><b>Genre</b></li>
+      <li><b>Author</b></li>
+      <li><b>Format</b></li>
+    </ul>
+  <h2>Reminder</h2>
+  <p>
+    1. Currently <b>supported extensions:</b>.
   </p>
     <ul>
       <li><b>.xlsx</b></li>
     </ul>
   <p>
-    3. All <b>new genres</b> used in the excel <b>will be created</b>.
+    2. All <b>new genres</b> used in the excel <b>will be created</b>.
   </p>
   <p>
-    4. All <b>new formats</b> used in the excel <b>will be created</b>.
+    3. All <b>new formats</b> used in the excel <b>will be created</b>.
   </p>
   <p>
-    5. Books are <b>identified by their ISBN</b>. This has the following consequences:</p>
+    4. Books are <b>identified by their ISBN</b>. This has the following consequences:</p>
     <ul>
-      <li>If the ISBN is <b>not assigned yet</b>, the book will be <b>added</b>.</li>
-      <li>If the ISBN is <b>already assigned</b>, the book will be <b>updated</b>.</li>
+      <li>If the ISBN is <b>not assigned yet</b>, a new book will be <b>added</b>.</li>
+      <li>If the ISBN is <b>already assigned</b>, the existing book will be <b>updated</b>.</li>
     </ul>
 </div>
 

src/app/components/book/book-excel-parser/book-excel-parser.component.ts

@@ -44,6 +44,8 @@ export class BookExcelParserComponent implements AfterViewInit{
 
   protected parsedData: Book[] = [];
 
+  protected fileReader = new FileReader();
+
   /**
    * Constructor
    * @param {BookService} service - The BookService for handling book-related operations.
@@ -108,22 +110,16 @@ export class BookExcelParserComponent implements AfterViewInit{
       const file = event.target.files[0];
 
       if(file && requiredFileType(file, allowedParserExtensions)){
-        let fileReader = new FileReader();
-
         this.isLoading = true;
 
-        fileReader.readAsBinaryString(file);
+        this.fileReader.readAsBinaryString(file);
 
-        fileReader.onload = (e) => {
+        this.fileReader.onload = (e) => {
           this.parsedData = [];
 
           this.excelSelected = true;
 
-          const workBook = XLSX.read(fileReader.result, {type:'binary'});
-
-          const sheetNames = workBook.SheetNames;
-
-          this.data = XLSX.utils.sheet_to_json(workBook.Sheets[sheetNames[0]]);
+          this.readExcelWorkBook();
 
           this.dataSource.data = this.data;
 
@@ -141,6 +137,22 @@ export class BookExcelParserComponent implements AfterViewInit{
     }
   }
 
+  /**
+   * Reads an Excel workbook and extracts data from all its sheets into a single array.
+   * This method is useful for processing Excel files in web applications where data from multiple sheets needs to be combined or displayed together.
+   */
+  private readExcelWorkBook() {
+    const workBook = XLSX.read(this.fileReader.result, {type:'binary'});
+
+    const sheetNames = workBook.SheetNames;
+
+    for (let index = 0; index < sheetNames.length; index++) {
+      const sheetName = sheetNames[index];
+      const sheet = workBook.Sheets[sheetName]
+      this.data = this.data.concat(XLSX.utils.sheet_to_json(sheet));
+    }
+  }
+
   /**
    * Parses each Excel book entry into a Book and populates the parsedData array.
    */