index.js
async function mapFiles (customizeResult, targetDir, callback) {
  const files = mergeEngineResults(customizeResult)
  const results = mapValues(files, (file, filename) => {
    // Write each file
    const fullpath = path.join(targetDir, filename)
    return callback(fullpath, file.contents)
  })
  return deep(results)
}
async function mapFiles (customizeResult, targetDir, callback) {
  const files = mergeEngineResults(customizeResult)
  const results = mapValues(files, (file, filename) => {
    // Write each file
    const fullpath = path.join(targetDir, filename)
    return callback(fullpath, file.contents)
  })
  return deep(results)
}
async function mapFiles ( customizeResult , targetDir , callback ) { const files = mergeEngineResults ( customizeResult ) const results = mapValues ( files , ( file , filename ) => { // Write each file const fullpath = path . join ( targetDir , filename ) return callback ( fullpath , file . contents ) } ) return deep ( results ) }
Map the merged files in the customize-result onto a function a promised object of values.

The type T is the return value of the callback (promised)

@param {object<object<string|Buffer|Readable|undefined>>} customizeResult
@param {function(fullpath: string, contents: (string|Buffer|Readable|undefined)):Promise<T>} callback functions that is called for each file
@return {Promise<object<T>>}
Map the merged files in the customize - result onto a function a promised object of values .