How to use

extension

function

in

Array

const result = [];
files.forEach(function (file, index) {
  if (typeof Render[file.extension] === 'function') {
    result[file.extension] = result[file.extension] ? result[file.extension] + 1 : 1;
    const content = Render.extract(file);
    if (content.fm.ignore) {
      destination,
      data: Object.assign({ filename: file.shortPath }, content.fm),
      type: file.extension,
    });
    result.push(page);