tasks/task-3-script-babel.js
function sourceRootFn (file) {
  let sourcePath    = file.history[0],
      targetPath    = path.join(__dirname, '../src/'),
      relativePath  = path.join(path.relative(sourcePath, targetPath), './src');
  return relativePath;
}
function sourceRootFn (file) {
  let sourcePath    = file.history[0],
      targetPath    = path.join(__dirname, '../src/'),
      relativePath  = path.join(path.relative(sourcePath, targetPath), './src');
  return relativePath;
}
function sourceRootFn ( file ) { let sourcePath = file . history [ 0 ] , targetPath = path . join ( __dirname , '../src/' ) , relativePath = path . join ( path . relative ( sourcePath , targetPath ) , './src' ) ; return relativePath ; }
Composes source-maps' sourceRoot property for a file
@param {any} file File being processed
@returns {any} sourceRoot value
Composes source - maps sourceRoot property for a file