How to use the pdfjs-dist.SVGGraphics function in pdfjs-dist

return page.getOperatorList().then(opList => {
          var svgGfx = new pdfjs.SVGGraphics(page.commonObjs, page.objs)
          svgGfx.embedFonts = true
          return svgGfx.getSVG(opList, viewport).then(svg => {
            return svg.toString()
              .replace('xmlns:svg', 'xmlns') // strip :svg to allow skipping namespace
              .replace(/<(\/|)svg:/g, '<$1') // strip namespaces added by pdf.js
          })
        })
      })

const previewAndIndexEachPage = async function(ctx, pagesDir, pageNum, doc) {
  try {
    const page = await doc.getPage(pageNum);
    const viewport = page.getViewport({ scale: viewportScale });
    ctx.addPreview(getFilePathForPage(pagesDir, pageNum, 'html'), 'html');
    ctx.addPreview(getFilePathForPage(pagesDir, pageNum, 'svg'), 'svg');

    const opList = await page.getOperatorList();
    const svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
    svgGfx.embedFonts = true;

    const svg = await svgGfx.getSVG(opList, viewport);

    await writeSvgToFile(svg, getFilePathForPage(pagesDir, pageNum, 'html'));
    await writeSvgToFile(svg, getFilePathForPage(pagesDir, pageNum, 'svg'));
    const content = await page.getTextContent();

    // Content contains lots of information about the text layout and
    // styles, but we need only strings at the moment
    const pageContents = _.pluck(content.items, 'str').join(' ');
    const pageName = util.format('page.%s.txt', pageNum);
    const pagePath = util.format('%s/%s', pagesDir, pageName);

    pdfContents.push(pageContents);
    ctx.addPreview(pagePath, pageName);

return page.getOperatorList().then(opList => {
                            let svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
                            svgGfx.embedFonts = true;
                            for (let i = 0; i < opList.fnArray.length; i++) {
                                if (opList.fnArray[i] === pdfjsLib.OPS.paintJpegXObject) {
                                    let imageInfo = page.objs.get(opList.argsArray[i][0]);
                                    extractedImages.push(imageInfo._src.split('data:image/jpeg;base64,')[1]);
                                }
                            }
                        });
                    });

.then((operatorList) => {
        const svgGfx = new pdfjs.SVGGraphics(page.commonObjs, page.objs);
        this.renderer = svgGfx.getSVG(operatorList, this.viewport)
          .then((svg) => {
            this.setState({ svg }, this.onRenderSuccess);
          })
          .catch(this.onRenderError);
      })
      .catch(this.onRenderError);

const loadingTask = pdfjsLib.getDocument({
        data,
        nativeImageDecoderSupport: 'display',
        CMapReaderFactory: NodeCMapReaderFactory
    })
    const doc = await loadingTask.promise
    const page = await doc.getPage(options.pageNumber)

    let viewport = page.getViewport({ scale: 1.0, })
    const height = options.height
    const width = options.width
    const scale = Math.min(height/viewport.height, width/viewport.width, 1)
    viewport = page.getViewport({ scale })

    const opList = await page.getOperatorList()
    const svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs)
    svgGfx.embedFonts = true
    const svg = await svgGfx.getSVG(opList, viewport)
    return svg.toString()
}

return page.getOperatorList().then((opList) => {
			let svgGfx = new pdfjsLib.SVGGraphics(page.commonObjs, page.objs);
			svgGfx.embedFonts = true;
			return svgGfx.getSVG(opList, viewport);
		}).then((svgDomElement) => {
			return this.svgWriter.writeSvgPage(page, svgDomElement);