function readFile(fileEntry) {

    fileEntry.file(function (file) {
        var reader = new FileReader();

        reader.onloadend = function() {
            console.log("Successful file read: " + this.result);
            displayFileData(fileEntry.fullPath + ": " + this.result);
        };

        reader.readAsText(file);

    }, onErrorReadFile);
}

export default function (fileName: string): Promise<string> {
  return new Promise((resolve) => {
    window.resolveLocalFileSystemURL(cordova.file.dataDirectory, dir => {
      dir.filesystem.root.getFile(fileName, { create: false }, fileEntry => {
        fileEntry.file(function (file) {
          const reader = new FileReader()
          reader.onloadend = function () {
            resolve(String(this.result))
          }
          reader.readAsText(file)
        })
      })
    })
  })
}