return forEachAncestorDirectory(searchPath, ancestor => {

const fileName = combinePaths(ancestor, configName);

return fileExists(fileName) ? fileName : undefined;

});

const basePath = getDirectoryPath(containingFile);

const referencedFileName = isRootedDiskPath(moduleName) ? moduleName : combinePaths(basePath, moduleName);

return normalizePath(referencedFileName);

let commonPathComponents: string[] | undefined;

const failed = forEach(fileNames, sourceFile => {

// Each file contributes into common source file path

const sourcePathComponents = getNormalizedPathComponents(sourceFile, currentDirectory);

sourcePathComponents.pop(); // The base file name is not part of the common directory path

if (!commonPathComponents) {

// first file

commonPathComponents = sourcePathComponents;

return;

}

const n = Math.min(commonPathComponents.length, sourcePathComponents.length);

for (let i = 0; i < n; i++) {

if (getCanonicalFileName(commonPathComponents[i]) !== getCanonicalFileName(sourcePathComponents[i])) {

if (i === 0) {

// Failed to find any common path component

return true;

}

// New common path found that is 0 -> i-1

commonPathComponents.length = i;

break;

}

}

// If the sourcePathComponents was shorter than the commonPathComponents, truncate to the sourcePathComponents

if (sourcePathComponents.length < commonPathComponents.length) {

commonPathComponents.length = sourcePathComponents.length;

}

});

// A common path can not be found when paths span multiple drives on windows, for example

if (failed) {

return "";

}

if (!commonPathComponents) { // Can happen when all input files are .d.ts files

return currentDirectory;

}

return getPathFromPathComponents(commonPathComponents);

const existingDirectories = new Map<string, boolean>();

const getCanonicalFileName = createGetCanonicalFileName(system.useCaseSensitiveFileNames);

function getSourceFile(fileName: string, languageVersionOrOptions: ScriptTarget | CreateSourceFileOptions, onError?: (message: string) => void): SourceFile | undefined {

let text: string | undefined;

try {

performance.mark("beforeIORead");

text = compilerHost.readFile(fileName);

performance.mark("afterIORead");

performance.measure("I/O Read", "beforeIORead", "afterIORead");

}

catch (e) {

if (onError) {

onError(e.message);

}

text = "";

}

return text !== undefined ? createSourceFile(fileName, text, languageVersionOrOptions, setParentNodes) : undefined;

}

function directoryExists(directoryPath: string): boolean {

if (existingDirectories.has(directoryPath)) {

return true;

}

if ((compilerHost.directoryExists || system.directoryExists)(directoryPath)) {

existingDirectories.set(directoryPath, true);

return true;

}

return false;

}

function writeFile(fileName: string, data: string, writeByteOrderMark: boolean, onError?: (message: string) => void) {

try {

performance.mark("beforeIOWrite");

// NOTE: If patchWriteFileEnsuringDirectory has been called,

// the system.writeFile will do its own directory creation and

// the ensureDirectoriesExist call will always be redundant.

writeFileEnsuringDirectories(

fileName,

data,

writeByteOrderMark,

(path, data, writeByteOrderMark) => system.writeFile(path, data, writeByteOrderMark),

path => (compilerHost.createDirectory || system.createDirectory)(path),

path => directoryExists(path));

performance.mark("afterIOWrite");

performance.measure("I/O Write", "beforeIOWrite", "afterIOWrite");

}

catch (e) {

if (onError) {

onError(e.message);

}

}

}

function getDefaultLibLocation(): string {

return getDirectoryPath(normalizePath(system.getExecutingFilePath()));

}

const newLine = getNewLineCharacter(options, () => system.newLine);

const realpath = system.realpath && ((path: string) => system.realpath!(path));

const compilerHost: CompilerHost = {

getSourceFile,

getDefaultLibLocation,

getDefaultLibFileName: options => combinePaths(getDefaultLibLocation(), getDefaultLibFileName(options)),

writeFile,

getCurrentDirectory: memoize(() => system.getCurrentDirectory()),

useCaseSensitiveFileNames: () => system.useCaseSensitiveFileNames,

getCanonicalFileName,

getNewLine: () => newLine,

fileExists: fileName => system.fileExists(fileName),

readFile: fileName => system.readFile(fileName),

trace: (s: string) => system.write(s + newLine),

directoryExists: directoryName => system.directoryExists(directoryName),

getEnvironmentVariable: name => system.getEnvironmentVariable ? system.getEnvironmentVariable(name) : "",

getDirectories: (path: string) => system.getDirectories(path),

realpath,

readDirectory: (path, extensions, include, exclude, depth) => system.readDirectory(path, extensions, include, exclude, depth),

createDirectory: d => system.createDirectory(d),

createHash: maybeBind(system, system.createHash)

};

return compilerHost;

fileExists(fileName: string): boolean;

readFile(fileName: string, encoding?: string): string | undefined;

directoryExists?(directory: string): boolean;

createDirectory?(directory: string): void;

writeFile?: WriteFileCallback;

host: CompilerHostLikeForCache,

toPath: (fileName: string) => Path,

getSourceFile?: CompilerHost["getSourceFile"]

) {

const originalReadFile = host.readFile;

const originalFileExists = host.fileExists;

const originalDirectoryExists = host.directoryExists;

const originalCreateDirectory = host.createDirectory;

const originalWriteFile = host.writeFile;

const readFileCache = new Map<string, string | false>();

const fileExistsCache = new Map<string, boolean>();

const directoryExistsCache = new Map<string, boolean>();

const sourceFileCache = new Map<string, SourceFile>();

const readFileWithCache = (fileName: string): string | undefined => {

const key = toPath(fileName);

const value = readFileCache.get(key);

if (value !== undefined) return value !== false ? value : undefined;

return setReadFileCache(key, fileName);

};

const setReadFileCache = (key: Path, fileName: string) => {

const newValue = originalReadFile.call(host, fileName);

readFileCache.set(key, newValue !== undefined ? newValue : false);

return newValue;

};

host.readFile = fileName => {

const key = toPath(fileName);

const value = readFileCache.get(key);

if (value !== undefined) return value !== false ? value : undefined; // could be .d.ts from output

// Cache json or buildInfo

if (!fileExtensionIs(fileName, Extension.Json) && !isBuildInfoFile(fileName)) {

return originalReadFile.call(host, fileName);

}

return setReadFileCache(key, fileName);

};

const getSourceFileWithCache: CompilerHost["getSourceFile"] | undefined = getSourceFile ? (fileName, languageVersion, onError, shouldCreateNewSourceFile) => {

const key = toPath(fileName);

const value = sourceFileCache.get(key);

if (value) return value;

const sourceFile = getSourceFile(fileName, languageVersion, onError, shouldCreateNewSourceFile);

if (sourceFile && (isDeclarationFileName(fileName) || fileExtensionIs(fileName, Extension.Json))) {

sourceFileCache.set(key, sourceFile);

}

return sourceFile;

} : undefined;

// fileExists for any kind of extension

host.fileExists = fileName => {

const key = toPath(fileName);

const value = fileExistsCache.get(key);

if (value !== undefined) return value;

const newValue = originalFileExists.call(host, fileName);

fileExistsCache.set(key, !!newValue);

return newValue;

};

if (originalWriteFile) {

host.writeFile = (fileName, data, ...rest) => {

const key = toPath(fileName);

fileExistsCache.delete(key);

const value = readFileCache.get(key);

if (value !== undefined && value !== data) {

readFileCache.delete(key);

sourceFileCache.delete(key);

}

else if (getSourceFileWithCache) {

const sourceFile = sourceFileCache.get(key);

if (sourceFile && sourceFile.text !== data) {

sourceFileCache.delete(key);

}

}

originalWriteFile.call(host, fileName, data, ...rest);

};

}

// directoryExists

if (originalDirectoryExists) {

host.directoryExists = directory => {

const key = toPath(directory);

const value = directoryExistsCache.get(key);

if (value !== undefined) return value;

const newValue = originalDirectoryExists.call(host, directory);

directoryExistsCache.set(key, !!newValue);

return newValue;

};

if (originalCreateDirectory) {

host.createDirectory = directory => {

const key = toPath(directory);

directoryExistsCache.delete(key);

originalCreateDirectory.call(host, directory);

};

}

}

return {

originalReadFile,

originalFileExists,

originalDirectoryExists,

originalCreateDirectory,

originalWriteFile,

getSourceFileWithCache,

readFileWithCache

};

let diagnostics: Diagnostic[] | undefined;

diagnostics = addRange(diagnostics, program.getConfigFileParsingDiagnostics());

diagnostics = addRange(diagnostics, program.getOptionsDiagnostics(cancellationToken));

diagnostics = addRange(diagnostics, program.getSyntacticDiagnostics(sourceFile, cancellationToken));

diagnostics = addRange(diagnostics, program.getGlobalDiagnostics(cancellationToken));

diagnostics = addRange(diagnostics, program.getSemanticDiagnostics(sourceFile, cancellationToken));

if (getEmitDeclarations(program.getCompilerOptions())) {

diagnostics = addRange(diagnostics, program.getDeclarationDiagnostics(sourceFile, cancellationToken));

}

return sortAndDeduplicateDiagnostics(diagnostics || emptyArray);

getCurrentDirectory(): string;

getCanonicalFileName(fileName: string): string;

getNewLine(): string;

let output = "";

for (const diagnostic of diagnostics) {

output += formatDiagnostic(diagnostic, host);

}

return output;

const errorMessage = `${diagnosticCategoryName(diagnostic)} TS${diagnostic.code}: ${flattenDiagnosticMessageText(diagnostic.messageText, host.getNewLine())}${host.getNewLine()}`;

if (diagnostic.file) {

const { line, character } = getLineAndCharacterOfPosition(diagnostic.file, diagnostic.start!); // TODO: GH#18217

const fileName = diagnostic.file.fileName;

const relativeFileName = convertToRelativePath(fileName, host.getCurrentDirectory(), fileName => host.getCanonicalFileName(fileName));

return `${relativeFileName}(${line + 1},${character + 1}): ` + errorMessage;

}

return errorMessage;

Grey = "\u001b[90m",

Red = "\u001b[91m",

Yellow = "\u001b[93m",

Blue = "\u001b[94m",

Cyan = "\u001b[96m"

switch (category) {

case DiagnosticCategory.Error: return ForegroundColorEscapeSequences.Red;

case DiagnosticCategory.Warning: return ForegroundColorEscapeSequences.Yellow;

case DiagnosticCategory.Suggestion: return Debug.fail("Should never get an Info diagnostic on the command line.");

case DiagnosticCategory.Message: return ForegroundColorEscapeSequences.Blue;

}

const { line: firstLine, character: firstLineChar } = getLineAndCharacterOfPosition(file, start);

const { line: lastLine, character: lastLineChar } = getLineAndCharacterOfPosition(file, start + length);

const lastLineInFile = getLineAndCharacterOfPosition(file, file.text.length).line;

const hasMoreThanFiveLines = (lastLine - firstLine) >= 4;

let gutterWidth = (lastLine + 1 + "").length;

if (hasMoreThanFiveLines) {

gutterWidth = Math.max(ellipsis.length, gutterWidth);

}

let context = "";

for (let i = firstLine; i <= lastLine; i++) {

context += host.getNewLine();

// If the error spans over 5 lines, we'll only show the first 2 and last 2 lines,

// so we'll skip ahead to the second-to-last line.

if (hasMoreThanFiveLines && firstLine + 1 < i && i < lastLine - 1) {

context += indent + formatColorAndReset(padLeft(ellipsis, gutterWidth), gutterStyleSequence) + gutterSeparator + host.getNewLine();

i = lastLine - 1;

}

const lineStart = getPositionOfLineAndCharacter(file, i, 0);

const lineEnd = i < lastLineInFile ? getPositionOfLineAndCharacter(file, i + 1, 0) : file.text.length;

let lineContent = file.text.slice(lineStart, lineEnd);

lineContent = trimStringEnd(lineContent); // trim from end

lineContent = lineContent.replace(/\t/g, " "); // convert tabs to single spaces

// Output the gutter and the actual contents of the line.

context += indent + formatColorAndReset(padLeft(i + 1 + "", gutterWidth), gutterStyleSequence) + gutterSeparator;

context += lineContent + host.getNewLine();

// Output the gutter and the error span for the line using tildes.

context += indent + formatColorAndReset(padLeft("", gutterWidth), gutterStyleSequence) + gutterSeparator;

context += squiggleColor;

if (i === firstLine) {

// If we're on the last line, then limit it to the last character of the last line.

// Otherwise, we'll just squiggle the rest of the line, giving 'slice' no end position.

const lastCharForLine = i === lastLine ? lastLineChar : undefined;

context += lineContent.slice(0, firstLineChar).replace(/\S/g, " ");

context += lineContent.slice(firstLineChar, lastCharForLine).replace(/./g, "~");

}

else if (i === lastLine) {

context += lineContent.slice(0, lastLineChar).replace(/./g, "~");

}

else {

// Squiggle the entire line.

context += lineContent.replace(/./g, "~");

}

context += resetEscapeSequence;

}

return context;

const { line: firstLine, character: firstLineChar } = getLineAndCharacterOfPosition(file, start); // TODO: GH#18217

const relativeFileName = host ? convertToRelativePath(file.fileName, host.getCurrentDirectory(), fileName => host.getCanonicalFileName(fileName)) : file.fileName;

let output = "";

output += color(relativeFileName, ForegroundColorEscapeSequences.Cyan);

output += ":";

output += color(`${firstLine + 1}`, ForegroundColorEscapeSequences.Yellow);

output += ":";

output += color(`${firstLineChar + 1}`, ForegroundColorEscapeSequences.Yellow);

return output;

let output = "";

for (const diagnostic of diagnostics) {

if (diagnostic.file) {

const { file, start } = diagnostic;

output += formatLocation(file, start!, host); // TODO: GH#18217

output += " - ";

}

output += formatColorAndReset(diagnosticCategoryName(diagnostic), getCategoryFormat(diagnostic.category));

output += formatColorAndReset(` TS${diagnostic.code}: `, ForegroundColorEscapeSequences.Grey);

output += flattenDiagnosticMessageText(diagnostic.messageText, host.getNewLine());

if (diagnostic.file) {

output += host.getNewLine();

output += formatCodeSpan(diagnostic.file, diagnostic.start!, diagnostic.length!, "", getCategoryFormat(diagnostic.category), host); // TODO: GH#18217

}

if (diagnostic.relatedInformation) {

output += host.getNewLine();

for (const { file, start, length, messageText } of diagnostic.relatedInformation) {

if (file) {

output += host.getNewLine();

output += halfIndent + formatLocation(file, start!, host); // TODO: GH#18217

output += formatCodeSpan(file, start!, length!, indent, ForegroundColorEscapeSequences.Cyan, host); // TODO: GH#18217

}

output += host.getNewLine();

output += indent + flattenDiagnosticMessageText(messageText, host.getNewLine());

}

}

output += host.getNewLine();

}

return output;

if (isString(diag)) {

return diag;

}

else if (diag === undefined) {

return "";

}

let result = "";

if (indent) {

result += newLine;

for (let i = 0; i < indent; i++) {

result += " ";

}

}

result += diag.messageText;

indent++;

if (diag.next) {

for (const kid of diag.next) {

result += flattenDiagnosticMessageText(kid, newLine, indent);

}

}

return result;

if (names.length === 0) {

return [];

}

const resolutions: T[] = [];

const cache = new Map<string, T>();

for (const name of names) {

let result: T;

const mode = getModeForFileReference(name, containingFileMode);

// We lower-case all type references because npm automatically lowercases all packages. See GH#9824.

const strName = isString(name) ? name : name.fileName.toLowerCase();

const cacheKey = mode !== undefined ? `${mode}|${strName}` : strName;

if (cache.has(cacheKey)) {

result = cache.get(cacheKey)!;

}

else {

cache.set(cacheKey, result = loader(strName, containingFile, redirectedReference, mode));

}

resolutions.push(result);

}

return resolutions;

/* @internal */ imports: SourceFile["imports"];

/* @internal */ moduleAugmentations: SourceFile["moduleAugmentations"];

impliedNodeFormat?: SourceFile["impliedNodeFormat"];

if (file.impliedNodeFormat === undefined) return undefined;

// we ensure all elements of file.imports and file.moduleAugmentations have the relevant parent pointers set during program setup,

// so it's safe to use them even pre-bind

return getModeForUsageLocation(file, getModuleNameStringLiteralAt(file, index));

if (isExportDeclaration(decl)) {

return decl.isTypeOnly;

}

if (decl.importClause?.isTypeOnly) {

return true;

}

return false;

if (file.impliedNodeFormat === undefined) return undefined;

if ((isImportDeclaration(usage.parent) || isExportDeclaration(usage.parent))) {

const isTypeOnly = isExclusivelyTypeOnlyImportOrExport(usage.parent);

if (isTypeOnly) {

const override = getResolutionModeOverrideForClause(usage.parent.assertClause);

if (override) {

return override;

}

}

}

if (usage.parent.parent && isImportTypeNode(usage.parent.parent)) {

const override = getResolutionModeOverrideForClause(usage.parent.parent.assertions?.assertClause);

if (override) {

return override;

}

}

if (file.impliedNodeFormat !== ModuleKind.ESNext) {

// in cjs files, import call expressions are esm format, otherwise everything is cjs

return isImportCall(walkUpParenthesizedExpressions(usage.parent)) ? ModuleKind.ESNext : ModuleKind.CommonJS;

}

// in esm files, import=require statements are cjs format, otherwise everything is esm

// imports are only parent'd up to their containing declaration/expression, so access farther parents with care

const exprParentParent = walkUpParenthesizedExpressions(usage.parent)?.parent;

return exprParentParent && isImportEqualsDeclaration(exprParentParent) ? ModuleKind.CommonJS : ModuleKind.ESNext;

if (!clause) return undefined;

if (length(clause.elements) !== 1) {

grammarErrorOnNode?.(clause, Diagnostics.Type_import_assertions_should_have_exactly_one_key_resolution_mode_with_value_import_or_require);

return undefined;

}

const elem = clause.elements[0];

if (!isStringLiteralLike(elem.name)) return undefined;

if (elem.name.text !== "resolution-mode") {

grammarErrorOnNode?.(elem.name, Diagnostics.resolution_mode_is_the_only_valid_key_for_type_import_assertions);

return undefined;

}

if (!isStringLiteralLike(elem.value)) return undefined;

if (elem.value.text !== "import" && elem.value.text !== "require") {

grammarErrorOnNode?.(elem.value, Diagnostics.resolution_mode_should_be_either_require_or_import);

return undefined;

}

return elem.value.text === "import" ? ModuleKind.ESNext : ModuleKind.CommonJS;

if (names.length === 0) {

return [];

}

const resolutions: T[] = [];

const cache = new Map<string, T>();

let i = 0;

for (const name of names) {

let result: T;

const mode = getModeForResolutionAtIndex(containingFile, i);

i++;

const cacheKey = mode !== undefined ? `${mode}|${name}` : name;

if (cache.has(cacheKey)) {

result = cache.get(cacheKey)!;

}

else {

cache.set(cacheKey, result = loader(name, mode, containingFileName, redirectedReference));

}

resolutions.push(result);

}

return resolutions;

resolvedProjectReferences: readonly (ResolvedProjectReference | undefined)[] | undefined,

cb: (resolvedProjectReference: ResolvedProjectReference, parent: ResolvedProjectReference | undefined) => T | undefined

): T | undefined {

return forEachProjectReference(/*projectReferences*/ undefined, resolvedProjectReferences, (resolvedRef, parent) => resolvedRef && cb(resolvedRef, parent));

projectReferences: readonly ProjectReference[] | undefined,

resolvedProjectReferences: readonly (ResolvedProjectReference | undefined)[] | undefined,

cbResolvedRef: (resolvedRef: ResolvedProjectReference | undefined, parent: ResolvedProjectReference | undefined, index: number) => T | undefined,

cbRef?: (projectReferences: readonly ProjectReference[] | undefined, parent: ResolvedProjectReference | undefined) => T | undefined

): T | undefined {

let seenResolvedRefs: Set<Path> | undefined;

return worker(projectReferences, resolvedProjectReferences, /*parent*/ undefined);

function worker(

projectReferences: readonly ProjectReference[] | undefined,

resolvedProjectReferences: readonly (ResolvedProjectReference | undefined)[] | undefined,

parent: ResolvedProjectReference | undefined,

): T | undefined {

// Visit project references first

if (cbRef) {

const result = cbRef(projectReferences, parent);

if (result) return result;

}

return forEach(resolvedProjectReferences, (resolvedRef, index) => {

if (resolvedRef && seenResolvedRefs?.has(resolvedRef.sourceFile.path)) {

// ignore recursives

return undefined;

}

const result = cbResolvedRef(resolvedRef, parent, index);

if (result || !resolvedRef) return result;

(seenResolvedRefs ||= new Set()).add(resolvedRef.sourceFile.path);

return worker(resolvedRef.commandLine.projectReferences, resolvedRef.references, resolvedRef);

});

}

switch (reason?.kind) {

case FileIncludeKind.Import:

case FileIncludeKind.ReferenceFile:

case FileIncludeKind.TypeReferenceDirective:

case FileIncludeKind.LibReferenceDirective:

return true;

default:

return false;

}

file: SourceFile;

pos: number;

end: number;