fixedWidth = function(str/*: string*/) {
  const WIDTH = 80;
  const strs = str.match(new RegExp(`(.{1,${WIDTH}})`, 'g')) || [str];
  let lastString = strs[strs.length - 1];
  if (lastString.length < WIDTH) {
    lastString += Array(WIDTH - lastString.length).join(chalk.dim('.'));
  }
  return strs
    .slice(0, -1)
    .concat(lastString)
    .join('\n');
}
script to build (transpile) files.
By default it transpiles all files for all packages and writes them
into `build/` directory.
Non-js or files matching IGNORE_PATTERN will be copied without transpiling.

Example:
 node ./scripts/build.js
 node ./scripts/build.js /user/c/metro/packages/metro-abc/src/abc.js