export function isCompatibleWithUserAgent()

in src/amo/utils/compatibility.js [154:238]
52 lines of code
17 McCabe index (conditional complexity)

export function isCompatibleWithUserAgent({
  _log = log,
  addon,
  currentVersion,
  maxVersion,
  minVersion,
  userAgentInfo,
}: IsCompatibleWithUserAgentParams): UserAgentCompatibilityType {
  // If the userAgent is false there was likely a programming error.
  invariant(userAgentInfo, 'userAgentInfo is required');

  const { browser } = userAgentInfo;

  // We need a Firefox browser compatible with add-ons (Firefox for iOS does
  // not currently support add-ons).
  if (isFirefoxForIOS(userAgentInfo)) {
    return { compatible: false, reason: INCOMPATIBLE_FIREFOX_FOR_IOS };
  }

  if (!isFirefox({ userAgentInfo })) {
    return { compatible: false, reason: INCOMPATIBLE_NOT_FIREFOX };
  }

  if (isFirefoxForAndroid(userAgentInfo)) {
    // We need to check that the add-on is installable and compatible.
    if (
      !isAndroidInstallable({ addon }) ||
      (currentVersion && !currentVersion.compatibility[CLIENT_APP_ANDROID])
    ) {
      return { compatible: false, reason: INCOMPATIBLE_ANDROID_UNSUPPORTED };
    }
  }

  // At this point we need a currentVersion and a file in order for an
  // extension to be marked as compatible.
  if (!currentVersion || !currentVersion.file) {
    return {
      compatible: false,
      reason: INCOMPATIBLE_UNSUPPORTED_PLATFORM,
    };
  }

  if (isFirefoxWithOldRootCerts({ userAgentInfo })) {
    return { compatible: false, reason: INCOMPATIBLE_OLD_ROOT_CERT_VERSION };
  }

  // Do version checks, if this add-on has minimum or maximum version
  // requirements.
  // The addons-moz-compare API is quite strange; a result of
  // `1` means the first argument is higher in version than the second.
  //
  // Being over the maxVersion, oddly, is not actually a reason to
  // disable the install button or mark the add-on as incompatible
  // with this version of Firefox. But we log the version mismatch
  // here so it's not totally silent and a future developer isn't as
  // confused by this as tofumatt was.
  // See: https://github.com/mozilla/addons-frontend/issues/2074#issuecomment-286983423
  if (maxVersion && mozCompare(browser.version, maxVersion) === 1) {
    if (currentVersion.isStrictCompatibilityEnabled) {
      return { compatible: false, reason: INCOMPATIBLE_OVER_MAX_VERSION };
    }

    _log.info(oneLine`maxVersion ${maxVersion} for add-on lower than
      browser version ${browser.version}, but add-on still marked as
      compatible because we largely ignore maxVersion. See:
      https://github.com/mozilla/addons-frontend/issues/2074`);
  }

  // A result of `-1` means the first argument is a lower version than the
  // second.
  if (minVersion && mozCompare(browser.version, minVersion) === -1) {
    if (minVersion === '*') {
      _log.error(oneLine`minVersion of "*" was passed to
        isCompatibleWithUserAgent(); bad add-on version data (browserVersion:
        ${browser.version})`);
    }

    // `minVersion` is always respected, regardless of
    // `isStrictCompatibilityEnabled`'s value.
    return { compatible: false, reason: INCOMPATIBLE_UNDER_MIN_VERSION };
  }

  // If we made it here we're compatible (yay!)
  return { compatible: true, reason: null };
}