Function watchPresentFileSystemEntry

test/fixtures/snapshot/typescript.js:7269–7300

* Watch the file or directory that is currently present * and when the watched file or directory is deleted, switch to missing file system entry watcher

()

                 * and when the watched file or directory is deleted, switch to missing file system entry watcher
                 */
                function watchPresentFileSystemEntry() {
                    // Node 4.0 `fs.watch` function supports the "recursive" option on both OSX and Windows
                    // (ref: https://github.com/nodejs/node/pull/2649 and https://github.com/Microsoft/TypeScript/issues/4643)
                    if (options === undefined) {
                        if (fsSupportsRecursiveFsWatch) {
                            options = { persistent: true, recursive: !!recursive };
                        }
                        else {
                            options = { persistent: true };
                        }
                    }
                    if (hitSystemWatcherLimit) {
                        sysLog("sysLog:: ".concat(fileOrDirectory, ":: Defaulting to fsWatchFile"));
                        return watchPresentFileSystemEntryWithFsWatchFile();
                    }
                    try {
                        var presentWatcher = _fs.watch(fileOrDirectory, options, isLinuxOrMacOs ?
                            callbackChangingToMissingFileSystemEntry :
                            callback);
                        // Watch the missing file or directory or error
                        presentWatcher.on("error", function () { return invokeCallbackAndUpdateWatcher(watchMissingFileSystemEntry); });
                        return presentWatcher;
                    }
                    catch (e) {
                        // Catch the exception and use polling instead
                        // Eg. on linux the number of watches are limited and one could easily exhaust watches and the exception ENOSPC is thrown when creating watcher at that point
                        // so instead of throwing error, use fs.watchFile
                        hitSystemWatcherLimit || (hitSystemWatcherLimit = e.code === "ENOSPC");
                        sysLog("sysLog:: ".concat(fileOrDirectory, ":: Changing to fsWatchFile"));
                        return watchPresentFileSystemEntryWithFsWatchFile();
                    }
                }
                function callbackChangingToMissingFileSystemEntry(event, relativeName) {
                    // because relativeName is not guaranteed to be correct we need to check on each rename with few combinations
                    // Eg on ubuntu while watching app/node_modules the relativeName is "node_modules" which is neither relative nor full path