public PlatformDetectorResult Detect()

in src/Detector/Node/NodeDetector.cs [37:139]
93 lines of code
17 McCabe index (conditional complexity)

        public PlatformDetectorResult Detect(DetectorContext context)
        {
            bool isNodeApp = false;
            bool hasLernaJsonFile = false;
            bool hasLageConfigJSFile = false;
            bool hasYarnrcYmlFile = false;
            bool IsYarnLockFileValidYamlFormat = false;
            string appDirectory = string.Empty;
            string lernaNpmClient = string.Empty;
            var sourceRepo = context.SourceRepo;
            if (sourceRepo.FileExists(NodeConstants.PackageJsonFileName) ||
                sourceRepo.FileExists(NodeConstants.PackageLockJsonFileName) ||
                sourceRepo.FileExists(NodeConstants.YarnLockFileName))
            {
                isNodeApp = true;
            }
            else
            {
                _logger.LogDebug(
                    $"Could not find {NodeConstants.PackageJsonFileName}/{NodeConstants.PackageLockJsonFileName}" +
                    $"/{NodeConstants.YarnLockFileName} in repo");
            }
            if (sourceRepo.FileExists(NodeConstants.YarnrcYmlName))
            {
                hasYarnrcYmlFile = true;
            }
            if (sourceRepo.FileExists(NodeConstants.YarnLockFileName)
                && IsYarnLockFileYamlFile(sourceRepo, NodeConstants.YarnLockFileName)) {
                IsYarnLockFileValidYamlFormat = true;
            }
            if (sourceRepo.FileExists(NodeConstants.LernaJsonFileName))
            {
                hasLernaJsonFile = true;
                lernaNpmClient = GetLernaJsonNpmClient(context);
            }
            if (sourceRepo.FileExists(NodeConstants.LageConfigJSFileName))
            {
                hasLageConfigJSFile = true;
            }

            if (!isNodeApp)
            {
                // Copying the logic currently running in Kudu:
                var mightBeNode = false;
                foreach (var typicalNodeFile in NodeConstants.TypicalNodeDetectionFiles)
                {
                    if (sourceRepo.FileExists(typicalNodeFile))
                    {
                        mightBeNode = true;
                        break;
                    }
                }

                if (mightBeNode)
                {
                    // Check if any of the known iis start pages exist
                    // If so, then it is not a node.js web site otherwise it is
                    foreach (var iisStartupFile in NodeConstants.IisStartupFiles)
                    {
                        if (sourceRepo.FileExists(iisStartupFile))
                        {
                            _logger.LogDebug(
                                "App in repo is not a Node.js app as it has the file {iisStartupFile}",
                                iisStartupFile.Hash());
                            return null;
                        }
                    }

                    isNodeApp = true;
                }
                else
                {
                    // No point in logging the actual file list, as it's constant
                    _logger.LogDebug("Could not find typical Node.js files in repo");
                }
            }

            if (!isNodeApp)
            {
                _logger.LogDebug("App in repo is not a NodeJS app");
                return null;
            }

            var version = GetVersion(context);
            IEnumerable<FrameworkInfo> detectedFrameworkInfos = null;
            if (!_options.DisableFrameworkDetection)
            {
                detectedFrameworkInfos = DetectFrameworkInfos(context);
            }

            return new NodePlatformDetectorResult
            {
                Platform = NodeConstants.PlatformName,
                PlatformVersion = version,
                AppDirectory = appDirectory,
                Frameworks = detectedFrameworkInfos,
                HasLernaJsonFile = hasLernaJsonFile,
                HasLageConfigJSFile = hasLageConfigJSFile,
                LernaNpmClient = lernaNpmClient,
                HasYarnrcYmlFile = hasYarnrcYmlFile,
                IsYarnLockFileValidYamlFormat = IsYarnLockFileValidYamlFormat,
            };
        }