function checkYarnVersion()

in packages/create-react-app/createReactApp.js [758:788]

• 27 lines of code
• 4 McCabe index (conditional complexity)

function checkYarnVersion() {
  const minYarnPnp = '1.12.0';
  const maxYarnPnp = '2.0.0';
  let hasMinYarnPnp = false;
  let hasMaxYarnPnp = false;
  let yarnVersion = null;
  try {
    yarnVersion = execSync('yarnpkg --version').toString().trim();
    if (semver.valid(yarnVersion)) {
      hasMinYarnPnp = semver.gte(yarnVersion, minYarnPnp);
      hasMaxYarnPnp = semver.lt(yarnVersion, maxYarnPnp);
    } else {
      // Handle non-semver compliant yarn version strings, which yarn currently
      // uses for nightly builds. The regex truncates anything after the first
      // dash. See #5362.
      const trimmedYarnVersionMatch = /^(.+?)[-+].+$/.exec(yarnVersion);
      if (trimmedYarnVersionMatch) {
        const trimmedYarnVersion = trimmedYarnVersionMatch.pop();
        hasMinYarnPnp = semver.gte(trimmedYarnVersion, minYarnPnp);
        hasMaxYarnPnp = semver.lt(trimmedYarnVersion, maxYarnPnp);
      }
    }
  } catch (err) {
    // ignore
  }
  return {
    hasMinYarnPnp: hasMinYarnPnp,
    hasMaxYarnPnp: hasMaxYarnPnp,
    yarnVersion: yarnVersion,
  };
}