Function nonRecursiveWatchDirectory

test/fixtures/snapshot/typescript.js:6858–6878

(directoryName, callback, recursive, options)

            return hostRecursiveDirectoryWatcher(directoryName, callback, recursive, options);
        }
        function nonRecursiveWatchDirectory(directoryName, callback, recursive, options) {
            ts.Debug.assert(!recursive);
            var watchDirectoryOptions = updateOptionsForWatchDirectory(options);
            var watchDirectoryKind = ts.Debug.checkDefined(watchDirectoryOptions.watchDirectory);
            switch (watchDirectoryKind) {
                case ts.WatchDirectoryKind.FixedPollingInterval:
                    return pollingWatchFile(directoryName, function () { return callback(directoryName); }, PollingInterval.Medium, 
                    /*options*/ undefined);
                case ts.WatchDirectoryKind.DynamicPriorityPolling:
                    return ensureDynamicPollingWatchFile()(directoryName, function () { return callback(directoryName); }, PollingInterval.Medium, 
                    /*options*/ undefined);
                case ts.WatchDirectoryKind.FixedChunkSizePolling:
                    return ensureFixedChunkSizePollingWatchFile()(directoryName, function () { return callback(directoryName); }, 
                    /* pollingInterval */ undefined, 
                    /*options*/ undefined);
                case ts.WatchDirectoryKind.UseFsEvents:
                    return fsWatch(directoryName, 1 /* FileSystemEntryKind.Directory */, createFsWatchCallbackForDirectoryWatcherCallback(directoryName, callback, options, useCaseSensitiveFileNames, getCurrentDirectory), recursive, PollingInterval.Medium, ts.getFallbackOptions(watchDirectoryOptions));
                default:
                    ts.Debug.assertNever(watchDirectoryKind);
            }
        }
        function updateOptionsForWatchDirectory(options) {
            if (options && options.watchDirectory !== undefined)
                return options;