startRecordingFilesWithChangedResolutions(): void;

finishRecordingFilesWithChangedResolutions(): Path[];

resolveModuleNames(moduleNames: string[], containingFile: string, reusedNames: string[] | undefined, logChanges: boolean): ResolvedModuleFull[];

resolveTypeReferenceDirectives(typeDirectiveNames: string[], containingFile: string): ResolvedTypeReferenceDirective[];

invalidateResolutionOfFile(filePath: Path): void;

removeResolutionsOfFile(filePath: Path): void;

createHasInvalidatedResolution(): HasInvalidatedResolution;

startCachingPerDirectoryResolution(): void;

finishCachingPerDirectoryResolution(): void;

updateTypeRootsWatch(): void;

closeTypeRootsWatch(): void;

clear(): void;

toPath(fileName: string): Path;

getCompilationSettings(): CompilerOptions;

watchDirectoryOfFailedLookupLocation(directory: string, cb: DirectoryWatcherCallback, flags: WatchDirectoryFlags): FileWatcher;

onInvalidatedResolution(): void;

watchTypeRootsDirectory(directory: string, cb: DirectoryWatcherCallback, flags: WatchDirectoryFlags): FileWatcher;

onChangedAutomaticTypeDirectiveNames(): void;

getCachedDirectoryStructureHost?(): CachedDirectoryStructureHost;

projectName?: string;

getGlobalCache?(): string | undefined;

writeLog(s: string): void;

maxNumberOfFilesToIterateForInvalidation?: number;

/** watcher for the directory of failed lookup */

watcher: FileWatcher;

/** ref count keeping this directory watch alive */

refCount: number;

dir: string;

dirPath: Path;

ignore?: true;

let filesWithChangedSetOfUnresolvedImports: Path[] | undefined;

let filesWithInvalidatedResolutions: Map<true> | undefined;

let allFilesHaveInvalidatedResolution = false;

// The resolvedModuleNames and resolvedTypeReferenceDirectives are the cache of resolutions per file.

// The key in the map is source file's path.

// The values are Map of resolutions with key being name lookedup.

const resolvedModuleNames = createMap<Map<ResolvedModuleWithFailedLookupLocations>>();

const perDirectoryResolvedModuleNames = createMap<Map<ResolvedModuleWithFailedLookupLocations>>();

const resolvedTypeReferenceDirectives = createMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();

const perDirectoryResolvedTypeReferenceDirectives = createMap<Map<ResolvedTypeReferenceDirectiveWithFailedLookupLocations>>();

const getCurrentDirectory = memoize(() => resolutionHost.getCurrentDirectory());

/**

const failedLookupDefaultExtensions = [Extension.Ts, Extension.Tsx, Extension.Js, Extension.Jsx, Extension.Json];

const customFailedLookupPaths = createMap<number>();

const directoryWatchesOfFailedLookups = createMap<DirectoryWatchesOfFailedLookup>();

const rootDir = rootDirForResolution && removeTrailingDirectorySeparator(getNormalizedAbsolutePath(rootDirForResolution, getCurrentDirectory()));

const rootPath = rootDir && resolutionHost.toPath(rootDir);

// TypeRoot watches for the types that get added as part of getAutomaticTypeDirectiveNames

const typeRootsWatches = createMap<FileWatcher>();

return {

startRecordingFilesWithChangedResolutions,

finishRecordingFilesWithChangedResolutions,

// perDirectoryResolvedModuleNames and perDirectoryResolvedTypeReferenceDirectives could be non empty if there was exception during program update

// (between startCachingPerDirectoryResolution and finishCachingPerDirectoryResolution)

startCachingPerDirectoryResolution: clearPerDirectoryResolutions,

finishCachingPerDirectoryResolution,

resolveModuleNames,

resolveTypeReferenceDirectives,

removeResolutionsOfFile,

invalidateResolutionOfFile,

createHasInvalidatedResolution,

updateTypeRootsWatch,

closeTypeRootsWatch,

clear

};

function getResolvedModule(resolution: ResolvedModuleWithFailedLookupLocations) {

return resolution.resolvedModule;

}

function getResolvedTypeReferenceDirective(resolution: ResolvedTypeReferenceDirectiveWithFailedLookupLocations) {

return resolution.resolvedTypeReferenceDirective;

}

function isInDirectoryPath(dir: Path, file: Path) {

if (dir === undefined || file.length <= dir.length) {

return false;

}

return startsWith(file, dir) && file[dir.length] === directorySeparator;

}

function clear() {

clearMap(directoryWatchesOfFailedLookups, closeFileWatcherOf);

customFailedLookupPaths.clear();

closeTypeRootsWatch();

resolvedModuleNames.clear();

resolvedTypeReferenceDirectives.clear();

allFilesHaveInvalidatedResolution = false;

// perDirectoryResolvedModuleNames and perDirectoryResolvedTypeReferenceDirectives could be non empty if there was exception during program update

// (between startCachingPerDirectoryResolution and finishCachingPerDirectoryResolution)

clearPerDirectoryResolutions();

}

function startRecordingFilesWithChangedResolutions() {

filesWithChangedSetOfUnresolvedImports = [];

}

function finishRecordingFilesWithChangedResolutions() {

const collected = filesWithChangedSetOfUnresolvedImports;

filesWithChangedSetOfUnresolvedImports = undefined;

return collected;

}

function createHasInvalidatedResolution(): HasInvalidatedResolution {

if (allFilesHaveInvalidatedResolution) {

// Any file asked would have invalidated resolution

filesWithInvalidatedResolutions = undefined;

return returnTrue;

}

const collected = filesWithInvalidatedResolutions;

filesWithInvalidatedResolutions = undefined;

return path => collected && collected.has(path);

}

function clearPerDirectoryResolutions() {

perDirectoryResolvedModuleNames.clear();

perDirectoryResolvedTypeReferenceDirectives.clear();

}

function finishCachingPerDirectoryResolution() {

allFilesHaveInvalidatedResolution = false;

directoryWatchesOfFailedLookups.forEach((watcher, path) => {

if (watcher.refCount === 0) {

directoryWatchesOfFailedLookups.delete(path);

watcher.watcher.close();

}

});

clearPerDirectoryResolutions();

}

function resolveModuleName(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {

const primaryResult = ts.resolveModuleName(moduleName, containingFile, compilerOptions, host);

// return result immediately only if global cache support is not enabled or if it is .ts, .tsx or .d.ts

if (!resolutionHost.getGlobalCache) {

return primaryResult;

}

// otherwise try to load typings from @types

const globalCache = resolutionHost.getGlobalCache();

if (globalCache !== undefined && !isExternalModuleNameRelative(moduleName) && !(primaryResult.resolvedModule && extensionIsTypeScript(primaryResult.resolvedModule.extension))) {

// create different collection of failed lookup locations for second pass

// if it will fail and we've already found something during the first pass - we don't want to pollute its results

const { resolvedModule, failedLookupLocations } = loadModuleFromGlobalCache(moduleName, resolutionHost.projectName, compilerOptions, host, globalCache);

if (resolvedModule) {

return { resolvedModule, failedLookupLocations: addRange(primaryResult.failedLookupLocations as string[], failedLookupLocations) };

}

}

// Default return the result from the first pass

return primaryResult;

}

function resolveNamesWithLocalCache<T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName>(

names: string[],

containingFile: string,

cache: Map<Map<T>>,

perDirectoryCache: Map<Map<T>>,

loader: (name: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost) => T,

getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>,

reusedNames: string[] | undefined,

logChanges: boolean): R[] {

const path = resolutionHost.toPath(containingFile);

const resolutionsInFile = cache.get(path) || cache.set(path, createMap()).get(path);

const dirPath = getDirectoryPath(path);

let perDirectoryResolution = perDirectoryCache.get(dirPath);

if (!perDirectoryResolution) {

perDirectoryResolution = createMap();

perDirectoryCache.set(dirPath, perDirectoryResolution);

}

const resolvedModules: R[] = [];

const compilerOptions = resolutionHost.getCompilationSettings();

const seenNamesInFile = createMap<true>();

for (const name of names) {

let resolution = resolutionsInFile.get(name);

// Resolution is valid if it is present and not invalidated

if (!seenNamesInFile.has(name) &&

allFilesHaveInvalidatedResolution || !resolution || resolution.isInvalidated) {

const existingResolution = resolution;

const resolutionInDirectory = perDirectoryResolution.get(name);

if (resolutionInDirectory) {

resolution = resolutionInDirectory;

}

else {

resolution = loader(name, containingFile, compilerOptions, resolutionHost);

perDirectoryResolution.set(name, resolution);

}

resolutionsInFile.set(name, resolution);

if (resolution.failedLookupLocations) {

if (existingResolution && existingResolution.failedLookupLocations) {

watchAndStopWatchDiffFailedLookupLocations(resolution, existingResolution);

}

else {

watchFailedLookupLocationOfResolution(resolution, 0);

}

}

else if (existingResolution) {

stopWatchFailedLookupLocationOfResolution(existingResolution);

}

if (logChanges && filesWithChangedSetOfUnresolvedImports && !resolutionIsEqualTo(existingResolution, resolution)) {

filesWithChangedSetOfUnresolvedImports.push(path);

// reset log changes to avoid recording the same file multiple times

logChanges = false;

}

}

Debug.assert(resolution !== undefined && !resolution.isInvalidated);

seenNamesInFile.set(name, true);

resolvedModules.push(getResolutionWithResolvedFileName(resolution));

}

// Stop watching and remove the unused name

resolutionsInFile.forEach((resolution, name) => {

if (!seenNamesInFile.has(name) && !contains(reusedNames, name)) {

stopWatchFailedLookupLocationOfResolution(resolution);

resolutionsInFile.delete(name);

}

});

return resolvedModules;

function resolutionIsEqualTo(oldResolution: T, newResolution: T): boolean {

if (oldResolution === newResolution) {

return true;

}

if (!oldResolution || !newResolution || oldResolution.isInvalidated) {

return false;

}

const oldResult = getResolutionWithResolvedFileName(oldResolution);

const newResult = getResolutionWithResolvedFileName(newResolution);

if (oldResult === newResult) {

return true;

}

if (!oldResult || !newResult) {

return false;

}

return oldResult.resolvedFileName === newResult.resolvedFileName;

}

}

function resolveTypeReferenceDirectives(typeDirectiveNames: string[], containingFile: string): ResolvedTypeReferenceDirective[] {

return resolveNamesWithLocalCache(

typeDirectiveNames, containingFile,

resolvedTypeReferenceDirectives, perDirectoryResolvedTypeReferenceDirectives,

resolveTypeReferenceDirective, getResolvedTypeReferenceDirective,

/*reusedNames*/ undefined, /*logChanges*/ false

);

}

function resolveModuleNames(moduleNames: string[], containingFile: string, reusedNames: string[] | undefined, logChanges: boolean): ResolvedModuleFull[] {

return resolveNamesWithLocalCache(

moduleNames, containingFile,

resolvedModuleNames, perDirectoryResolvedModuleNames,

resolveModuleName, getResolvedModule,

reusedNames, logChanges

);

}

function isNodeModulesDirectory(dirPath: Path) {

return endsWith(dirPath, "/node_modules");

}

function isNodeModulesAtTypesDirectory(dirPath: Path) {

return endsWith(dirPath, "/node_modules/@types");

}

function isDirectoryAtleastAtLevelFromFSRoot(dirPath: Path, minLevels: number) {

for (let searchIndex = getRootLength(dirPath); minLevels > 0; minLevels--) {

searchIndex = dirPath.indexOf(directorySeparator, searchIndex) + 1;

if (searchIndex === 0) {

// Folder isnt at expected minimun levels

return false;

}

}

return true;

}

function canWatchDirectory(dirPath: Path) {

return isDirectoryAtleastAtLevelFromFSRoot(dirPath,

// When root is "/" do not watch directories like:

// "/", "/user", "/user/username", "/user/username/folderAtRoot"

// When root is "c:/" do not watch directories like:

// "c:/", "c:/folderAtRoot"

dirPath.charCodeAt(0) === CharacterCodes.slash ? 3 : 1);

}

function filterFSRootDirectoriesToWatch(watchPath: DirectoryOfFailedLookupWatch, dirPath: Path): DirectoryOfFailedLookupWatch {

if (!canWatchDirectory(dirPath)) {

watchPath.ignore = true;

}

return watchPath;

}

function getDirectoryToWatchFailedLookupLocation(failedLookupLocation: string, failedLookupLocationPath: Path): DirectoryOfFailedLookupWatch {

if (isInDirectoryPath(rootPath, failedLookupLocationPath)) {

return { dir: rootDir, dirPath: rootPath };

}

let dir = getDirectoryPath(getNormalizedAbsolutePath(failedLookupLocation, getCurrentDirectory()));

let dirPath = getDirectoryPath(failedLookupLocationPath);

// If directory path contains node module, get the most parent node_modules directory for watching

while (stringContains(dirPath, "/node_modules/")) {

dir = getDirectoryPath(dir);

dirPath = getDirectoryPath(dirPath);

}

// If the directory is node_modules use it to watch

if (isNodeModulesDirectory(dirPath)) {

return filterFSRootDirectoriesToWatch({ dir, dirPath }, getDirectoryPath(dirPath));

}

// Use some ancestor of the root directory

if (rootPath !== undefined) {

while (!isInDirectoryPath(dirPath, rootPath)) {

const parentPath = getDirectoryPath(dirPath);

if (parentPath === dirPath) {

break;

}

dirPath = parentPath;

dir = getDirectoryPath(dir);

}

}

return filterFSRootDirectoriesToWatch({ dir, dirPath }, dirPath);

}

function isPathWithDefaultFailedLookupExtension(path: Path) {

return fileExtensionIsOneOf(path, failedLookupDefaultExtensions);

}

function watchAndStopWatchDiffFailedLookupLocations(resolution: ResolutionWithFailedLookupLocations, existingResolution: ResolutionWithFailedLookupLocations) {

const failedLookupLocations = resolution.failedLookupLocations;

const existingFailedLookupLocations = existingResolution.failedLookupLocations;

for (let index = 0; index < failedLookupLocations.length; index++) {

if (index === existingFailedLookupLocations.length) {

// Additional failed lookup locations, watch from this index

watchFailedLookupLocationOfResolution(resolution, index);

return;

}

else if (failedLookupLocations[index] !== existingFailedLookupLocations[index]) {

// Different failed lookup locations,

// Watch new resolution failed lookup locations from this index and

// stop watching existing resolutions from this index

watchFailedLookupLocationOfResolution(resolution, index);

stopWatchFailedLookupLocationOfResolutionFrom(existingResolution, index);

return;

}

}

// All new failed lookup locations are already watched (and are same),

// Stop watching failed lookup locations of existing resolution after failed lookup locations length

stopWatchFailedLookupLocationOfResolutionFrom(existingResolution, failedLookupLocations.length);

}

function watchFailedLookupLocationOfResolution({ failedLookupLocations }: ResolutionWithFailedLookupLocations, startIndex: number) {

for (let i = startIndex; i < failedLookupLocations.length; i++) {

const failedLookupLocation = failedLookupLocations[i];

const failedLookupLocationPath = resolutionHost.toPath(failedLookupLocation);

// If the failed lookup location path is not one of the supported extensions,

// store it in the custom path

if (!isPathWithDefaultFailedLookupExtension(failedLookupLocationPath)) {

const refCount = customFailedLookupPaths.get(failedLookupLocationPath) || 0;

customFailedLookupPaths.set(failedLookupLocationPath, refCount + 1);

}

const { dir, dirPath, ignore } = getDirectoryToWatchFailedLookupLocation(failedLookupLocation, failedLookupLocationPath);

if (!ignore) {

const dirWatcher = directoryWatchesOfFailedLookups.get(dirPath);

if (dirWatcher) {

dirWatcher.refCount++;

}

else {

directoryWatchesOfFailedLookups.set(dirPath, { watcher: createDirectoryWatcher(dir, dirPath), refCount: 1 });

}

}

}

}

function stopWatchFailedLookupLocationOfResolution(resolution: ResolutionWithFailedLookupLocations) {

if (resolution.failedLookupLocations) {

stopWatchFailedLookupLocationOfResolutionFrom(resolution, 0);

}

}

function stopWatchFailedLookupLocationOfResolutionFrom({ failedLookupLocations }: ResolutionWithFailedLookupLocations, startIndex: number) {

for (let i = startIndex; i < failedLookupLocations.length; i++) {

const failedLookupLocation = failedLookupLocations[i];

const failedLookupLocationPath = resolutionHost.toPath(failedLookupLocation);

const refCount = customFailedLookupPaths.get(failedLookupLocationPath);

if (refCount) {

if (refCount === 1) {

customFailedLookupPaths.delete(failedLookupLocationPath);

}

else {

Debug.assert(refCount > 1);

customFailedLookupPaths.set(failedLookupLocationPath, refCount - 1);

}

}

const { dirPath, ignore } = getDirectoryToWatchFailedLookupLocation(failedLookupLocation, failedLookupLocationPath);

if (!ignore) {

const dirWatcher = directoryWatchesOfFailedLookups.get(dirPath);

// Do not close the watcher yet since it might be needed by other failed lookup locations.

dirWatcher.refCount--;

}

}

}

function createDirectoryWatcher(directory: string, dirPath: Path) {

return resolutionHost.watchDirectoryOfFailedLookupLocation(directory, fileOrDirectory => {

const fileOrDirectoryPath = resolutionHost.toPath(fileOrDirectory);

if (resolutionHost.getCachedDirectoryStructureHost) {

// Since the file existance changed, update the sourceFiles cache

resolutionHost.getCachedDirectoryStructureHost().addOrDeleteFileOrDirectory(fileOrDirectory, fileOrDirectoryPath);

}

// If the files are added to project root or node_modules directory, always run through the invalidation process

// Otherwise run through invalidation only if adding to the immediate directory

if (!allFilesHaveInvalidatedResolution &&

dirPath === rootPath || isNodeModulesDirectory(dirPath) || getDirectoryPath(fileOrDirectoryPath) === dirPath) {

if (invalidateResolutionOfFailedLookupLocation(fileOrDirectoryPath, dirPath === fileOrDirectoryPath)) {

resolutionHost.onInvalidatedResolution();

}

}

}, WatchDirectoryFlags.Recursive);

}

function removeResolutionsOfFileFromCache(cache: Map<Map<ResolutionWithFailedLookupLocations>>, filePath: Path) {

// Deleted file, stop watching failed lookups for all the resolutions in the file

const resolutions = cache.get(filePath);

if (resolutions) {

resolutions.forEach(stopWatchFailedLookupLocationOfResolution);

cache.delete(filePath);

}

}

function removeResolutionsOfFile(filePath: Path) {

removeResolutionsOfFileFromCache(resolvedModuleNames, filePath);

removeResolutionsOfFileFromCache(resolvedTypeReferenceDirectives, filePath);

}

function invalidateResolutionCache<T extends ResolutionWithFailedLookupLocations, R extends ResolutionWithResolvedFileName>(

cache: Map<Map<T>>,

isInvalidatedResolution: (resolution: T, getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>) => boolean,

getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName<T, R>

) {

const seen = createMap<Map<true>>();

cache.forEach((resolutions, containingFilePath) => {

const dirPath = getDirectoryPath(containingFilePath);

let seenInDir = seen.get(dirPath);

if (!seenInDir) {

seenInDir = createMap<true>();

seen.set(dirPath, seenInDir);

}

resolutions.forEach((resolution, name) => {

if (seenInDir.has(name)) {

return;

}

seenInDir.set(name, true);

if (!resolution.isInvalidated && isInvalidatedResolution(resolution, getResolutionWithResolvedFileName)) {

// Mark the file as needing re-evaluation of module resolution instead of using it blindly.

resolution.isInvalidated = true;

(filesWithInvalidatedResolutions || (filesWithInvalidatedResolutions = createMap<true>())).set(containingFilePath, true);

}

});

});

}

function hasReachedResolutionIterationLimit() {

const maxSize = resolutionHost.maxNumberOfFilesToIterateForInvalidation || maxNumberOfFilesToIterateForInvalidation;

return resolvedModuleNames.size > maxSize || resolvedTypeReferenceDirectives.size > maxSize;

}

function invalidateResolutions(

isInvalidatedResolution: (resolution: ResolutionWithFailedLookupLocations, getResolutionWithResolvedFileName: GetResolutionWithResolvedFileName) => boolean,

) {

// If more than maxNumberOfFilesToIterateForInvalidation present,

// just invalidated all files and recalculate the resolutions for files instead

if (hasReachedResolutionIterationLimit()) {

allFilesHaveInvalidatedResolution = true;

return;

}

invalidateResolutionCache(resolvedModuleNames, isInvalidatedResolution, getResolvedModule);

invalidateResolutionCache(resolvedTypeReferenceDirectives, isInvalidatedResolution, getResolvedTypeReferenceDirective);

}

function invalidateResolutionOfFile(filePath: Path) {

removeResolutionsOfFile(filePath);

invalidateResolutions(

// Resolution is invalidated if the resulting file name is same as the deleted file path

(resolution, getResolutionWithResolvedFileName) => {

const result = getResolutionWithResolvedFileName(resolution);

return result && resolutionHost.toPath(result.resolvedFileName) === filePath;

}

);

}

function invalidateResolutionOfFailedLookupLocation(fileOrDirectoryPath: Path, isCreatingWatchedDirectory: boolean) {

let isChangedFailedLookupLocation: (location: string) => boolean;

if (isCreatingWatchedDirectory) {

// Watching directory is created

// Invalidate any resolution has failed lookup in this directory

isChangedFailedLookupLocation = location => isInDirectoryPath(fileOrDirectoryPath, resolutionHost.toPath(location));

}

else {

// Some file or directory in the watching directory is created

// Return early if it does not have any of the watching extension or not the custom failed lookup path

const dirOfFileOrDirectory = getDirectoryPath(fileOrDirectoryPath);

if (isNodeModulesAtTypesDirectory(dirOfFileOrDirectory) || isNodeModulesDirectory(dirOfFileOrDirectory)) {

// Invalidate any resolution from this directory

isChangedFailedLookupLocation = location => {

const locationPath = resolutionHost.toPath(location);

return locationPath === fileOrDirectoryPath || startsWith(resolutionHost.toPath(location), fileOrDirectoryPath);

};

}

else {

if (!isPathWithDefaultFailedLookupExtension(fileOrDirectoryPath) && !customFailedLookupPaths.has(fileOrDirectoryPath)) {

return false;

}

// Resolution need to be invalidated if failed lookup location is same as the file or directory getting created

isChangedFailedLookupLocation = location => resolutionHost.toPath(location) === fileOrDirectoryPath;

}

}

const hasChangedFailedLookupLocation = (resolution: ResolutionWithFailedLookupLocations) => some(resolution.failedLookupLocations, isChangedFailedLookupLocation);

const invalidatedFilesCount = filesWithInvalidatedResolutions && filesWithInvalidatedResolutions.size;

invalidateResolutions(

// Resolution is invalidated if the resulting file name is same as the deleted file path

hasChangedFailedLookupLocation

);

return allFilesHaveInvalidatedResolution || filesWithInvalidatedResolutions && filesWithInvalidatedResolutions.size !== invalidatedFilesCount;

}

function closeTypeRootsWatch() {

clearMap(typeRootsWatches, closeFileWatcher);

}

function createTypeRootsWatch(_typeRootPath: string, typeRoot: string): FileWatcher {

// Create new watch and recursive info

return resolutionHost.watchTypeRootsDirectory(typeRoot, fileOrDirectory => {

const fileOrDirectoryPath = resolutionHost.toPath(fileOrDirectory);

if (resolutionHost.getCachedDirectoryStructureHost) {

// Since the file existance changed, update the sourceFiles cache

resolutionHost.getCachedDirectoryStructureHost().addOrDeleteFileOrDirectory(fileOrDirectory, fileOrDirectoryPath);

}

// For now just recompile

// We could potentially store more data here about whether it was/would be really be used or not

// and with that determine to trigger compilation but for now this is enough

resolutionHost.onChangedAutomaticTypeDirectiveNames();

}, WatchDirectoryFlags.Recursive);

}

/**

function updateTypeRootsWatch() {

const options = resolutionHost.getCompilationSettings();

if (options.types) {

// No need to do any watch since resolution cache is going to handle the failed lookups

// for the types added by this

closeTypeRootsWatch();

return;

}

// we need to assume the directories exist to ensure that we can get all the type root directories that get included

// But filter directories that are at root level to say directory doesnt exist, so that we arent watching them

const typeRoots = getEffectiveTypeRoots(options, { directoryExists: directoryExistsForTypeRootWatch, getCurrentDirectory });

if (typeRoots) {

mutateMap(

typeRootsWatches,

arrayToMap(typeRoots, tr => resolutionHost.toPath(tr)),

{

createNewValue: createTypeRootsWatch,

onDeleteValue: closeFileWatcher

}

);

}

else {

closeTypeRootsWatch();

}

}

/**

function directoryExistsForTypeRootWatch(nodeTypesDirectory: string) {

const dir = getDirectoryPath(getDirectoryPath(nodeTypesDirectory));

const dirPath = resolutionHost.toPath(dir);

return dirPath === rootPath || canWatchDirectory(dirPath);

}