code: function getFont(fontName, fontStyle, options) {
        var key = undefined,
            fontNameLowerCase;
        options = options || {};
        fontName = fontName !== undefined ? fontName : fonts[activeFontKey].fontName;
        fontStyle = fontStyle !== undefined ? fontStyle : fonts[activeFontKey].fontStyle;
        fontNameLowerCase = fontName.toLowerCase();
  
        if (fontmap[fontNameLowerCase] !== undefined && fontmap[fontNameLowerCase][fontStyle] !== undefined) {
          key = fontmap[fontNameLowerCase][fontStyle];
        } else if (fontmap[fontName] !== undefined && fontmap[fontName][fontStyle] !== undefined) {
          key = fontmap[fontName][fontStyle];
        } else {
          if (options.disableWarning === false) {
            console.warn("Unable to look up font label for font '" + fontName + "', '" + fontStyle + "'. Refer to getFontList() for available fonts.");
          }
        }
  
        if (!key && !options.noFallback) {
          key = fontmap['times'][fontStyle];
  
          if (key == null) {
            key = fontmap['times']['normal'];
          }
        }
  
        return key;
      }
docs: Returns a document-specific font key - a label assigned to a
  font name + font type combination at the time the font was added
  to the font inventory.
  
  Font key is used as label for the desired font for a block of text
  to be added to the PDF document stream.
  @private
  @function
  @param fontName {string} can be undefined on "falthy" to indicate "use current"
  @param fontStyle {string} can be undefined on "falthy" to indicate "use current"
  @returns {string} Font key.
  @ignore