Function maybeParallelizeCommand

build-system/pr-check/parallelization.js:30–42

* Splits command execution using a glob string on parallelized CircleCI builds. * * If no parallelization is detected, simply returns the command as-is. * If parallelization is detected, uses the glob to add an argument to the * command by passing it through an optional callback function. * *

(command, glob, callback = (s) => s)

 * @return {string} the CLI command that should be executed.
 */
function maybeParallelizeCommand(command, glob, callback = (s) => s) {
  if (!circleciIsParallelized()) {
    return command;
  }

  const tempFileName = tempy.file();
  timedExecOrDie(
    `circleci tests glob ${glob} | circleci tests run --command=">${tempFileName} xargs echo -n"`
  );
  const globAndRunResults = fs.readFileSync(tempFileName, {encoding: 'utf-8'});

  return `${command} ${callback(globAndRunResults)}`;
}

module.exports = {maybeParallelizeCommand};