Compare Two PDFs Side by Side Compare two PDF files side by side for differences.

Under the hood, it utilizes the pdfjs-dist library to parse PDF files and extract relevant information. When a PDF file is dropped into the tool, it uses the `arrayBuffer` method to read the file contents and then passes this data to the `getDocument` function from pdfjs-dist, which returns a promise that resolves to a PDF document object. The tool then extracts metadata such as title, author, creator, and producer from the PDF document's info dictionary using the `getMetadata` method. Additionally, it retrieves the first page of the PDF document using the `getPage` method and calculates its dimensions by getting the viewport with a scale factor of 1.

The extracted information is stored in a `PdfInfo` object, which contains properties such as file name, size, page count, page dimensions, title, author, creator, and producer. The tool uses two instances of this object to store the information for both PDF files being compared. When both PDFs have been loaded and their information extracted, the tool generates a comparison table with rows representing different properties such as file name, file size, page count, and page dimensions. Each row contains cells showing the values of these properties for both PDF files, along with a match indicator that displays "Yes" if the property values are identical and "No" otherwise.

The comparison table is generated using JavaScript's `map` function to iterate over an array of objects representing the different properties being compared. Each object in this array contains the label for the property, as well as the values of this property for both PDF files. The tool uses React to render this table and update it dynamically whenever new PDF files are loaded or the comparison results change. By performing all analysis client-side using JavaScript and the pdfjs-dist library, the tool ensures that sensitive documents are not uploaded to external servers, making it suitable for use with confidential information.