Pdfjslib.getdocument(…).then is not a function

Explanation

The error message “pdfjslib.getdocument(…).then is not a function” usually occurs when the method getdocument() is not a promise-based function and does not support the .then() method.

In JavaScript, the .then() method is used to handle the result of a promise. When a function is expected to return a promise, you can chain the .then() method to perform actions once the promise is resolved or rejected.

To resolve this error, you need to make sure that pdfjslib.getdocument() is returning a promise. Here’s an example on how to correctly use promises with pdfjslib.getdocument():

    
      pdfjslib.getdocument(url).promise.then(function(pdf) {
        // Here you can perform actions on the PDF document
        console.log("PDF loaded successfully!");

        // Example: render the first page
        pdf.getPage(1).then(function(page) {
          var scale = 1.5;
          var viewport = page.getViewport({ scale: scale });

          var canvas = document.getElementById('pdf-canvas');
          var context = canvas.getContext('2d');
          canvas.height = viewport.height;
          canvas.width = viewport.width;

          var renderContext = {
            canvasContext: context,
            viewport: viewport
          };
          page.render(renderContext);
        });
      }).catch(function(error) {
        console.log("Error loading PDF:", error);
      });
    
  

In the above example, pdfjslib.getdocument(url) returns a promise, and we can then chain the .then() method to access the loaded PDF document. Inside the .then() function, we can perform actions on the PDF document, such as rendering pages.