function ready(sources, externs) {
  const flags = Object.assign(Object.assign({}, argv), {jsCode: sources, externs: externs});
  const output = cmdCompile(flags);
  let code = 0;
  if (logger(flags, output)) {
    code = 1;
  }
  console.log(output.compiledCode);

  process.exit(code);
}
@param {!Array<{src: string, path: string}>} sources
@param {!Array<{src: string, path: string}>} externs