Repair PDF with JavaScript via C++

Aspose.PDF for JavaScript allows high-quality PDF repair. The PDF file may not open for any reason, regardless of the program or browser. In some cases the document can be restored, try the following code and see for yourself.

1. Create a ‘FileReader’.
2. The AsposePdfRepair function is executed.
3. The name of the resulting file is set, in this example “ResultPdfRepair.pdf”.
4. Next, if the ‘json.errorCode’ is 0, then you can get links to result files. If the ‘json.errorCode’ parameter is not equal to 0 and, accordingly, there will be an error in your file, then information about such an error will be contained in the ‘json.errorText’ file.
5. As a result, the DownloadFile function generates a link and allows you to download the resulting file to the user’s operating system.

    var ffilePdfRepair = function (e) {
      const file_reader = new FileReader();
      file_reader.onload = (event) => {
        /*Repair a PDF-file and save the "ResultPdfRepair.pdf"*/
        const json = AsposePdfRepair(event.target.result, e.target.files[0].name, "ResultPdfRepair.pdf");
        if (json.errorCode == 0) document.getElementById('output').textContent = json.fileNameResult;
        else document.getElementById('output').textContent = json.errorText;
        /*Make a link to download the result file*/
        DownloadFile(json.fileNameResult, "application/pdf");
      };
      file_reader.readAsArrayBuffer(e.target.files[0]);
    };

Using Web Workers

    /*Create Web Worker*/
    const AsposePDFWebWorker = new Worker("AsposePDFforJS.js");
    AsposePDFWebWorker.onerror = evt => console.log(`Error from Web Worker: ${evt.message}`);
    AsposePDFWebWorker.onmessage = evt => document.getElementById('output').textContent = 
      (evt.data == 'ready') ? 'loaded!' :
        (evt.data.json.errorCode == 0) ? `Result:\n${DownloadFile(evt.data.json.fileNameResult, "application/pdf", evt.data.params[0])}` : `Error: ${evt.data.json.errorText}`;

    /*Event handler*/
    const ffilePdfRepair = e => {
      const file_reader = new FileReader();
      file_reader.onload = event => {
        /*Repair a PDF-file and save the "ResultPdfRepair.pdf" - Ask Web Worker*/
        AsposePDFWebWorker.postMessage({ "operation": 'AsposePdfRepair', "params": [event.target.result, e.target.files[0].name, "ResultPdfRepair.pdf"] }, [event.target.result]);
      };
      file_reader.readAsArrayBuffer(e.target.files[0]);
    };
  /// [Code snippet]

    /*Make a link to download the result file*/
    const DownloadFile = (filename, mime, content) => {
        mime = mime || "application/octet-stream";
        var link = document.createElement("a"); 
        link.href = URL.createObjectURL(new Blob([content], {type: mime}));
        link.download = filename;
        link.innerHTML = "Click here to download the file " + filename;
        document.body.appendChild(link); 
        document.body.appendChild(document.createElement("br"));
        return filename;
      }