How to use the mini-svg-data-uri function in mini-svg-data-uri

.then(nd => {
      nd.setAttribute('xmlns', 'http://www.w3.org/1999/xhtml');
      const serializedString =  new window.XMLSerializer().serializeToString(nd);

      const xhtml = escapeXhtml(serializedString);
      const foreignObject = ``;
      const svgStr = `<svg height="${height}" width="${width}" xmlns="http://www.w3.org/2000/svg">${foreignObject}</svg>`;

      // Optimizing SVGs in data URIs
      // see https://codepen.io/tigt/post/optimizing-svgs-in-data-uris
      // the best way of encoding SVG in a data: URI is data:image/svg+xml,[actual data].
      // We don’t need the ;charset=utf-8 parameter because the given SVG is ASCII.
      return svgToMiniDataURI(svgStr);
    });
}

const getDataUri = filePath => {
  if (path.extname(filePath).toLowerCase() === '.svg') {
    const file = fs.readFileSync(filePath, 'utf-8')
    return svgDataUri(file)
  }

  const file = fs.readFileSync(filePath)
  return `data:${mimeLookup(filePath)};base64,${new Buffer(file).toString(
    'base64',
  )}`
}