file.js

import path from 'path';
import { getHomeDirectory, isDirectorySync } from 'fs-plus';
import isElectron from 'is-electron';
import glob from 'glob';

export const openFileSelector = (callback) => {
  if (isElectron()) {
    const remote = window.require('electron').remote;
    remote.dialog.showOpenDialog(
      remote.BrowserWindow.getFocusedWindow(),
      {
        title: 'Import',
        buttonLabel: 'Import',
        properties: [ 'openFile' ],
        defaultPath: remote.app.getPath('desktop'),
      },
      (results) => {
        if (results && results.length > 0) {
          const result = results[0];
          callback(null, encodeURIComponent('file://' + result), path.basename(result));
          storage.setItem('importFolder', path.dirname(result));
        } else {
          callback(null, null, null);
        }
      }
    )
  } else {
    let fileInput = document.querySelector('#global-file-input');
    if (!fileInput) {
      fileInput = document.createElement('input');
      fileInput.type = 'file';
      fileInput.style.display = 'none';
      fileInput.style.position = 'absolute';
      document.body.appendChild(fileInput);
    }
    const fileHandler = (e) => {
      fileInput.removeEventListener('change', fileHandler);
      if (fileInput.files.length > 0) {
        callback(null, URL.createObjectURL(fileInput.files[0]), fileInput.files[0].name);
      } else {
        callback(null, null, null);
      }
    }
    fileInput.addEventListener('change', fileHandler, false);
    fileInput.click();
  }
}