loading a pdf and rendering a page with pdf.js

sample-page-render-pdfjs.js

pdfjsLib.getDocument('helloworld.pdf')
  .then(pdf => pdf.getPage(1)
    .then(page => {
      var scale = 1.5
      var viewport = page.getViewport(scale)

      var canvas = document.createElement('canvas')
      var context = canvas.getContext('2d')
      canvas.height = viewport.height
      canvas.width = viewport.width

      var renderContext = {
        canvasContext: context,
        viewport: page.getViewport(scale)
      }
      
      page.render(renderContext)
    })
)