TypeScript/src/compiler/moduleNameResolver.ts

761 lines
40 KiB
TypeScript

/// <reference path="core.ts" />
/// <reference path="diagnosticInformationMap.generated.ts" />
namespace ts {
/* @internal */
export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void;
export function trace(host: ModuleResolutionHost, message: DiagnosticMessage): void {
host.trace(formatMessage.apply(undefined, arguments));
}
/* @internal */
export function isTraceEnabled(compilerOptions: CompilerOptions, host: ModuleResolutionHost): boolean {
return compilerOptions.traceResolution && host.trace !== undefined;
}
/* @internal */
export function createResolvedModule(resolvedFileName: string, isExternalLibraryImport: boolean, failedLookupLocations: string[]): ResolvedModuleWithFailedLookupLocations {
return { resolvedModule: resolvedFileName ? { resolvedFileName, isExternalLibraryImport } : undefined, failedLookupLocations };
}
function moduleHasNonRelativeName(moduleName: string): boolean {
return !(isRootedDiskPath(moduleName) || isExternalModuleNameRelative(moduleName));
}
/* @internal */
export interface ModuleResolutionState {
host: ModuleResolutionHost;
compilerOptions: CompilerOptions;
traceEnabled: boolean;
// skip .tsx files if jsx is not enabled
skipTsx: boolean;
}
function tryReadTypesSection(packageJsonPath: string, baseDirectory: string, state: ModuleResolutionState): string {
const jsonContent = readJson(packageJsonPath, state.host);
function tryReadFromField(fieldName: string) {
if (hasProperty(jsonContent, fieldName)) {
const typesFile = (<any>jsonContent)[fieldName];
if (typeof typesFile === "string") {
const typesFilePath = normalizePath(combinePaths(baseDirectory, typesFile));
if (state.traceEnabled) {
trace(state.host, Diagnostics.package_json_has_0_field_1_that_references_2, fieldName, typesFile, typesFilePath);
}
return typesFilePath;
}
else {
if (state.traceEnabled) {
trace(state.host, Diagnostics.Expected_type_of_0_field_in_package_json_to_be_string_got_1, fieldName, typeof typesFile);
}
}
}
}
const typesFilePath = tryReadFromField("typings") || tryReadFromField("types");
if (typesFilePath) {
return typesFilePath;
}
// Use the main module for inferring types if no types package specified and the allowJs is set
if (state.compilerOptions.allowJs && jsonContent.main && typeof jsonContent.main === "string") {
if (state.traceEnabled) {
trace(state.host, Diagnostics.No_types_specified_in_package_json_but_allowJs_is_set_so_returning_main_value_of_0, jsonContent.main);
}
const mainFilePath = normalizePath(combinePaths(baseDirectory, jsonContent.main));
return mainFilePath;
}
return undefined;
}
function readJson(path: string, host: ModuleResolutionHost): { typings?: string, types?: string, main?: string } {
try {
const jsonText = host.readFile(path);
return jsonText ? JSON.parse(jsonText) : {};
}
catch (e) {
// gracefully handle if readFile fails or returns not JSON
return {};
}
}
const typeReferenceExtensions = [".d.ts"];
export function getEffectiveTypeRoots(options: CompilerOptions, host: { directoryExists?: (directoryName: string) => boolean, getCurrentDirectory?: () => string }): string[] | undefined {
if (options.typeRoots) {
return options.typeRoots;
}
let currentDirectory: string;
if (options.configFilePath) {
currentDirectory = getDirectoryPath(options.configFilePath);
}
else if (host.getCurrentDirectory) {
currentDirectory = host.getCurrentDirectory();
}
return currentDirectory !== undefined && getDefaultTypeRoots(currentDirectory, host);
}
/**
* Returns the path to every node_modules/@types directory from some ancestor directory.
* Returns undefined if there are none.
*/
function getDefaultTypeRoots(currentDirectory: string, host: { directoryExists?: (directoryName: string) => boolean }): string[] | undefined {
if (!host.directoryExists) {
return [combinePaths(currentDirectory, nodeModulesAtTypes)];
// And if it doesn't exist, tough.
}
let typeRoots: string[];
while (true) {
const atTypes = combinePaths(currentDirectory, nodeModulesAtTypes);
if (host.directoryExists(atTypes)) {
(typeRoots || (typeRoots = [])).push(atTypes);
}
const parent = getDirectoryPath(currentDirectory);
if (parent === currentDirectory) {
break;
}
currentDirectory = parent;
}
return typeRoots;
}
const nodeModulesAtTypes = combinePaths("node_modules", "@types");
/**
* @param {string | undefined} containingFile - file that contains type reference directive, can be undefined if containing file is unknown.
* This is possible in case if resolution is performed for directives specified via 'types' parameter. In this case initial path for secondary lookups
* is assumed to be the same as root directory of the project.
*/
export function resolveTypeReferenceDirective(typeReferenceDirectiveName: string, containingFile: string, options: CompilerOptions, host: ModuleResolutionHost): ResolvedTypeReferenceDirectiveWithFailedLookupLocations {
const traceEnabled = isTraceEnabled(options, host);
const moduleResolutionState: ModuleResolutionState = {
compilerOptions: options,
host: host,
skipTsx: true,
traceEnabled
};
const typeRoots = getEffectiveTypeRoots(options, host);
if (traceEnabled) {
if (containingFile === undefined) {
if (typeRoots === undefined) {
trace(host, Diagnostics.Resolving_type_reference_directive_0_containing_file_not_set_root_directory_not_set, typeReferenceDirectiveName);
}
else {
trace(host, Diagnostics.Resolving_type_reference_directive_0_containing_file_not_set_root_directory_1, typeReferenceDirectiveName, typeRoots);
}
}
else {
if (typeRoots === undefined) {
trace(host, Diagnostics.Resolving_type_reference_directive_0_containing_file_1_root_directory_not_set, typeReferenceDirectiveName, containingFile);
}
else {
trace(host, Diagnostics.Resolving_type_reference_directive_0_containing_file_1_root_directory_2, typeReferenceDirectiveName, containingFile, typeRoots);
}
}
}
const failedLookupLocations: string[] = [];
// Check primary library paths
if (typeRoots && typeRoots.length) {
if (traceEnabled) {
trace(host, Diagnostics.Resolving_with_primary_search_path_0, typeRoots.join(", "));
}
const primarySearchPaths = typeRoots;
for (const typeRoot of primarySearchPaths) {
const candidate = combinePaths(typeRoot, typeReferenceDirectiveName);
const candidateDirectory = getDirectoryPath(candidate);
const resolvedFile = loadNodeModuleFromDirectory(typeReferenceExtensions, candidate, failedLookupLocations,
!directoryProbablyExists(candidateDirectory, host), moduleResolutionState);
if (resolvedFile) {
if (traceEnabled) {
trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, true);
}
return {
resolvedTypeReferenceDirective: { primary: true, resolvedFileName: resolvedFile },
failedLookupLocations
};
}
}
}
else {
if (traceEnabled) {
trace(host, Diagnostics.Root_directory_cannot_be_determined_skipping_primary_search_paths);
}
}
let resolvedFile: string;
let initialLocationForSecondaryLookup: string;
if (containingFile) {
initialLocationForSecondaryLookup = getDirectoryPath(containingFile);
}
if (initialLocationForSecondaryLookup !== undefined) {
// check secondary locations
if (traceEnabled) {
trace(host, Diagnostics.Looking_up_in_node_modules_folder_initial_location_0, initialLocationForSecondaryLookup);
}
resolvedFile = loadModuleFromNodeModules(typeReferenceDirectiveName, initialLocationForSecondaryLookup, failedLookupLocations, moduleResolutionState, /*checkOneLevel*/ false);
if (traceEnabled) {
if (resolvedFile) {
trace(host, Diagnostics.Type_reference_directive_0_was_successfully_resolved_to_1_primary_Colon_2, typeReferenceDirectiveName, resolvedFile, false);
}
else {
trace(host, Diagnostics.Type_reference_directive_0_was_not_resolved, typeReferenceDirectiveName);
}
}
}
else {
if (traceEnabled) {
trace(host, Diagnostics.Containing_file_is_not_specified_and_root_directory_cannot_be_determined_skipping_lookup_in_node_modules_folder);
}
}
return {
resolvedTypeReferenceDirective: resolvedFile
? { primary: false, resolvedFileName: resolvedFile }
: undefined,
failedLookupLocations
};
}
/**
* Given a set of options, returns the set of type directive names
* that should be included for this program automatically.
* This list could either come from the config file,
* or from enumerating the types root + initial secondary types lookup location.
* More type directives might appear in the program later as a result of loading actual source files;
* this list is only the set of defaults that are implicitly included.
*/
export function getAutomaticTypeDirectiveNames(options: CompilerOptions, host: ModuleResolutionHost): string[] {
// Use explicit type list from tsconfig.json
if (options.types) {
return options.types;
}
// Walk the primary type lookup locations
const result: string[] = [];
if (host.directoryExists && host.getDirectories) {
const typeRoots = getEffectiveTypeRoots(options, host);
if (typeRoots) {
for (const root of typeRoots) {
if (host.directoryExists(root)) {
for (const typeDirectivePath of host.getDirectories(root)) {
const normalized = normalizePath(typeDirectivePath);
const packageJsonPath = pathToPackageJson(combinePaths(root, normalized));
// tslint:disable-next-line:no-null-keyword
const isNotNeededPackage = host.fileExists(packageJsonPath) && readJson(packageJsonPath, host).typings === null;
if (!isNotNeededPackage) {
// Return just the type directive names
result.push(getBaseFileName(normalized));
}
}
}
}
}
}
return result;
}
export function resolveModuleName(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
const traceEnabled = isTraceEnabled(compilerOptions, host);
if (traceEnabled) {
trace(host, Diagnostics.Resolving_module_0_from_1, moduleName, containingFile);
}
let moduleResolution = compilerOptions.moduleResolution;
if (moduleResolution === undefined) {
moduleResolution = getEmitModuleKind(compilerOptions) === ModuleKind.CommonJS ? ModuleResolutionKind.NodeJs : ModuleResolutionKind.Classic;
if (traceEnabled) {
trace(host, Diagnostics.Module_resolution_kind_is_not_specified_using_0, ModuleResolutionKind[moduleResolution]);
}
}
else {
if (traceEnabled) {
trace(host, Diagnostics.Explicitly_specified_module_resolution_kind_Colon_0, ModuleResolutionKind[moduleResolution]);
}
}
let result: ResolvedModuleWithFailedLookupLocations;
switch (moduleResolution) {
case ModuleResolutionKind.NodeJs:
result = nodeModuleNameResolver(moduleName, containingFile, compilerOptions, host);
break;
case ModuleResolutionKind.Classic:
result = classicNameResolver(moduleName, containingFile, compilerOptions, host);
break;
}
if (traceEnabled) {
if (result.resolvedModule) {
trace(host, Diagnostics.Module_name_0_was_successfully_resolved_to_1, moduleName, result.resolvedModule.resolvedFileName);
}
else {
trace(host, Diagnostics.Module_name_0_was_not_resolved, moduleName);
}
}
return result;
}
/*
* Every module resolution kind can has its specific understanding how to load module from a specific path on disk
* I.e. for path '/a/b/c':
* - Node loader will first to try to check if '/a/b/c' points to a file with some supported extension and if this fails
* it will try to load module from directory: directory '/a/b/c' should exist and it should have either 'package.json' with
* 'typings' entry or file 'index' with some supported extension
* - Classic loader will only try to interpret '/a/b/c' as file.
*/
type ResolutionKindSpecificLoader = (candidate: string, extensions: string[], failedLookupLocations: string[], onlyRecordFailures: boolean, state: ModuleResolutionState) => string;
/**
* Any module resolution kind can be augmented with optional settings: 'baseUrl', 'paths' and 'rootDirs' - they are used to
* mitigate differences between design time structure of the project and its runtime counterpart so the same import name
* can be resolved successfully by TypeScript compiler and runtime module loader.
* If these settings are set then loading procedure will try to use them to resolve module name and it can of failure it will
* fallback to standard resolution routine.
*
* - baseUrl - this setting controls how non-relative module names are resolved. If this setting is specified then non-relative
* names will be resolved relative to baseUrl: i.e. if baseUrl is '/a/b' then candidate location to resolve module name 'c/d' will
* be '/a/b/c/d'
* - paths - this setting can only be used when baseUrl is specified. allows to tune how non-relative module names
* will be resolved based on the content of the module name.
* Structure of 'paths' compiler options
* 'paths': {
* pattern-1: [...substitutions],
* pattern-2: [...substitutions],
* ...
* pattern-n: [...substitutions]
* }
* Pattern here is a string that can contain zero or one '*' character. During module resolution module name will be matched against
* all patterns in the list. Matching for patterns that don't contain '*' means that module name must be equal to pattern respecting the case.
* If pattern contains '*' then to match pattern "<prefix>*<suffix>" module name must start with the <prefix> and end with <suffix>.
* <MatchedStar> denotes part of the module name between <prefix> and <suffix>.
* If module name can be matches with multiple patterns then pattern with the longest prefix will be picked.
* After selecting pattern we'll use list of substitutions to get candidate locations of the module and the try to load module
* from the candidate location.
* Substitution is a string that can contain zero or one '*'. To get candidate location from substitution we'll pick every
* substitution in the list and replace '*' with <MatchedStar> string. If candidate location is not rooted it
* will be converted to absolute using baseUrl.
* For example:
* baseUrl: /a/b/c
* "paths": {
* // match all module names
* "*": [
* "*", // use matched name as is,
* // <matched name> will be looked as /a/b/c/<matched name>
*
* "folder1/*" // substitution will convert matched name to 'folder1/<matched name>',
* // since it is not rooted then final candidate location will be /a/b/c/folder1/<matched name>
* ],
* // match module names that start with 'components/'
* "components/*": [ "/root/components/*" ] // substitution will convert /components/folder1/<matched name> to '/root/components/folder1/<matched name>',
* // it is rooted so it will be final candidate location
* }
*
* 'rootDirs' allows the project to be spreaded across multiple locations and resolve modules with relative names as if
* they were in the same location. For example lets say there are two files
* '/local/src/content/file1.ts'
* '/shared/components/contracts/src/content/protocols/file2.ts'
* After bundling content of '/shared/components/contracts/src' will be merged with '/local/src' so
* if file1 has the following import 'import {x} from "./protocols/file2"' it will be resolved successfully in runtime.
* 'rootDirs' provides the way to tell compiler that in order to get the whole project it should behave as if content of all
* root dirs were merged together.
* I.e. for the example above 'rootDirs' will have two entries: [ '/local/src', '/shared/components/contracts/src' ].
* Compiler will first convert './protocols/file2' into absolute path relative to the location of containing file:
* '/local/src/content/protocols/file2' and try to load it - failure.
* Then it will search 'rootDirs' looking for a longest matching prefix of this absolute path and if such prefix is found - absolute path will
* be converted to a path relative to found rootDir entry './content/protocols/file2' (*). As a last step compiler will check all remaining
* entries in 'rootDirs', use them to build absolute path out of (*) and try to resolve module from this location.
*/
function tryLoadModuleUsingOptionalResolutionSettings(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
failedLookupLocations: string[], supportedExtensions: string[], state: ModuleResolutionState): string {
if (moduleHasNonRelativeName(moduleName)) {
return tryLoadModuleUsingBaseUrl(moduleName, loader, failedLookupLocations, supportedExtensions, state);
}
else {
return tryLoadModuleUsingRootDirs(moduleName, containingDirectory, loader, failedLookupLocations, supportedExtensions, state);
}
}
function tryLoadModuleUsingRootDirs(moduleName: string, containingDirectory: string, loader: ResolutionKindSpecificLoader,
failedLookupLocations: string[], supportedExtensions: string[], state: ModuleResolutionState): string {
if (!state.compilerOptions.rootDirs) {
return undefined;
}
if (state.traceEnabled) {
trace(state.host, Diagnostics.rootDirs_option_is_set_using_it_to_resolve_relative_module_name_0, moduleName);
}
const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
let matchedRootDir: string;
let matchedNormalizedPrefix: string;
for (const rootDir of state.compilerOptions.rootDirs) {
// rootDirs are expected to be absolute
// in case of tsconfig.json this will happen automatically - compiler will expand relative names
// using location of tsconfig.json as base location
let normalizedRoot = normalizePath(rootDir);
if (!endsWith(normalizedRoot, directorySeparator)) {
normalizedRoot += directorySeparator;
}
const isLongestMatchingPrefix =
startsWith(candidate, normalizedRoot) &&
(matchedNormalizedPrefix === undefined || matchedNormalizedPrefix.length < normalizedRoot.length);
if (state.traceEnabled) {
trace(state.host, Diagnostics.Checking_if_0_is_the_longest_matching_prefix_for_1_2, normalizedRoot, candidate, isLongestMatchingPrefix);
}
if (isLongestMatchingPrefix) {
matchedNormalizedPrefix = normalizedRoot;
matchedRootDir = rootDir;
}
}
if (matchedNormalizedPrefix) {
if (state.traceEnabled) {
trace(state.host, Diagnostics.Longest_matching_prefix_for_0_is_1, candidate, matchedNormalizedPrefix);
}
const suffix = candidate.substr(matchedNormalizedPrefix.length);
// first - try to load from a initial location
if (state.traceEnabled) {
trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, matchedNormalizedPrefix, candidate);
}
const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(containingDirectory, state.host), state);
if (resolvedFileName) {
return resolvedFileName;
}
if (state.traceEnabled) {
trace(state.host, Diagnostics.Trying_other_entries_in_rootDirs);
}
// then try to resolve using remaining entries in rootDirs
for (const rootDir of state.compilerOptions.rootDirs) {
if (rootDir === matchedRootDir) {
// skip the initially matched entry
continue;
}
const candidate = combinePaths(normalizePath(rootDir), suffix);
if (state.traceEnabled) {
trace(state.host, Diagnostics.Loading_0_from_the_root_dir_1_candidate_location_2, suffix, rootDir, candidate);
}
const baseDirectory = getDirectoryPath(candidate);
const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(baseDirectory, state.host), state);
if (resolvedFileName) {
return resolvedFileName;
}
}
if (state.traceEnabled) {
trace(state.host, Diagnostics.Module_resolution_using_rootDirs_has_failed);
}
}
return undefined;
}
function tryLoadModuleUsingBaseUrl(moduleName: string, loader: ResolutionKindSpecificLoader, failedLookupLocations: string[],
supportedExtensions: string[], state: ModuleResolutionState): string {
if (!state.compilerOptions.baseUrl) {
return undefined;
}
if (state.traceEnabled) {
trace(state.host, Diagnostics.baseUrl_option_is_set_to_0_using_this_value_to_resolve_non_relative_module_name_1, state.compilerOptions.baseUrl, moduleName);
}
// string is for exact match
let matchedPattern: Pattern | string | undefined = undefined;
if (state.compilerOptions.paths) {
if (state.traceEnabled) {
trace(state.host, Diagnostics.paths_option_is_specified_looking_for_a_pattern_to_match_module_name_0, moduleName);
}
matchedPattern = matchPatternOrExact(getOwnKeys(state.compilerOptions.paths), moduleName);
}
if (matchedPattern) {
const matchedStar = typeof matchedPattern === "string" ? undefined : matchedText(matchedPattern, moduleName);
const matchedPatternText = typeof matchedPattern === "string" ? matchedPattern : patternText(matchedPattern);
if (state.traceEnabled) {
trace(state.host, Diagnostics.Module_name_0_matched_pattern_1, moduleName, matchedPatternText);
}
for (const subst of state.compilerOptions.paths[matchedPatternText]) {
const path = matchedStar ? subst.replace("*", matchedStar) : subst;
const candidate = normalizePath(combinePaths(state.compilerOptions.baseUrl, path));
if (state.traceEnabled) {
trace(state.host, Diagnostics.Trying_substitution_0_candidate_module_location_Colon_1, subst, path);
}
const resolvedFileName = loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
if (resolvedFileName) {
return resolvedFileName;
}
}
return undefined;
}
else {
const candidate = normalizePath(combinePaths(state.compilerOptions.baseUrl, moduleName));
if (state.traceEnabled) {
trace(state.host, Diagnostics.Resolving_module_name_0_relative_to_base_url_1_2, moduleName, state.compilerOptions.baseUrl, candidate);
}
return loader(candidate, supportedExtensions, failedLookupLocations, !directoryProbablyExists(getDirectoryPath(candidate), state.host), state);
}
}
export function nodeModuleNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
const containingDirectory = getDirectoryPath(containingFile);
const supportedExtensions = getSupportedExtensions(compilerOptions);
const traceEnabled = isTraceEnabled(compilerOptions, host);
const failedLookupLocations: string[] = [];
const state = { compilerOptions, host, traceEnabled, skipTsx: false };
let resolvedFileName = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, nodeLoadModuleByRelativeName,
failedLookupLocations, supportedExtensions, state);
let isExternalLibraryImport = false;
if (!resolvedFileName) {
if (moduleHasNonRelativeName(moduleName)) {
if (traceEnabled) {
trace(host, Diagnostics.Loading_module_0_from_node_modules_folder, moduleName);
}
resolvedFileName = loadModuleFromNodeModules(moduleName, containingDirectory, failedLookupLocations, state, /*checkOneLevel*/ false);
isExternalLibraryImport = resolvedFileName !== undefined;
}
else {
const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
resolvedFileName = nodeLoadModuleByRelativeName(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
}
}
if (resolvedFileName && host.realpath) {
const originalFileName = resolvedFileName;
resolvedFileName = normalizePath(host.realpath(resolvedFileName));
if (traceEnabled) {
trace(host, Diagnostics.Resolving_real_path_for_0_result_1, originalFileName, resolvedFileName);
}
}
return createResolvedModule(resolvedFileName, isExternalLibraryImport, failedLookupLocations);
}
function nodeLoadModuleByRelativeName(candidate: string, supportedExtensions: string[], failedLookupLocations: string[],
onlyRecordFailures: boolean, state: ModuleResolutionState): string {
if (state.traceEnabled) {
trace(state.host, Diagnostics.Loading_module_as_file_Slash_folder_candidate_module_location_0, candidate);
}
const resolvedFileName = !pathEndsWithDirectorySeparator(candidate) && loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, onlyRecordFailures, state);
return resolvedFileName || loadNodeModuleFromDirectory(supportedExtensions, candidate, failedLookupLocations, onlyRecordFailures, state);
}
/* @internal */
export function directoryProbablyExists(directoryName: string, host: { directoryExists?: (directoryName: string) => boolean }): boolean {
// if host does not support 'directoryExists' assume that directory will exist
return !host.directoryExists || host.directoryExists(directoryName);
}
/**
* @param {boolean} onlyRecordFailures - if true then function won't try to actually load files but instead record all attempts as failures. This flag is necessary
* in cases when we know upfront that all load attempts will fail (because containing folder does not exists) however we still need to record all failed lookup locations.
*/
function loadModuleFromFile(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
// First, try adding an extension. An import of "foo" could be matched by a file "foo.ts", or "foo.js" by "foo.js.ts"
const resolvedByAddingExtension = tryAddingExtensions(candidate, extensions, failedLookupLocation, onlyRecordFailures, state);
if (resolvedByAddingExtension) {
return resolvedByAddingExtension;
}
// If that didn't work, try stripping a ".js" or ".jsx" extension and replacing it with a TypeScript one;
// e.g. "./foo.js" can be matched by "./foo.ts" or "./foo.d.ts"
if (hasJavaScriptFileExtension(candidate)) {
const extensionless = removeFileExtension(candidate);
if (state.traceEnabled) {
const extension = candidate.substring(extensionless.length);
trace(state.host, Diagnostics.File_name_0_has_a_1_extension_stripping_it, candidate, extension);
}
return tryAddingExtensions(extensionless, extensions, failedLookupLocation, onlyRecordFailures, state);
}
}
/** Try to return an existing file that adds one of the `extensions` to `candidate`. */
function tryAddingExtensions(candidate: string, extensions: string[], failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
if (!onlyRecordFailures) {
// check if containing folder exists - if it doesn't then just record failures for all supported extensions without disk probing
const directory = getDirectoryPath(candidate);
if (directory) {
onlyRecordFailures = !directoryProbablyExists(directory, state.host);
}
}
return forEach(extensions, ext =>
!(state.skipTsx && isJsxOrTsxExtension(ext)) && tryFile(candidate + ext, failedLookupLocation, onlyRecordFailures, state));
}
/** Return the file if it exists. */
function tryFile(fileName: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string | undefined {
if (!onlyRecordFailures && state.host.fileExists(fileName)) {
if (state.traceEnabled) {
trace(state.host, Diagnostics.File_0_exist_use_it_as_a_name_resolution_result, fileName);
}
return fileName;
}
else {
if (state.traceEnabled) {
trace(state.host, Diagnostics.File_0_does_not_exist, fileName);
}
failedLookupLocation.push(fileName);
return undefined;
}
}
function loadNodeModuleFromDirectory(extensions: string[], candidate: string, failedLookupLocation: string[], onlyRecordFailures: boolean, state: ModuleResolutionState): string {
const packageJsonPath = pathToPackageJson(candidate);
const directoryExists = !onlyRecordFailures && directoryProbablyExists(candidate, state.host);
if (directoryExists && state.host.fileExists(packageJsonPath)) {
if (state.traceEnabled) {
trace(state.host, Diagnostics.Found_package_json_at_0, packageJsonPath);
}
const typesFile = tryReadTypesSection(packageJsonPath, candidate, state);
if (typesFile) {
const onlyRecordFailures = !directoryProbablyExists(getDirectoryPath(typesFile), state.host);
// A package.json "typings" may specify an exact filename, or may choose to omit an extension.
const result = tryFile(typesFile, failedLookupLocation, onlyRecordFailures, state) ||
tryAddingExtensions(typesFile, extensions, failedLookupLocation, onlyRecordFailures, state);
if (result) {
return result;
}
}
else {
if (state.traceEnabled) {
trace(state.host, Diagnostics.package_json_does_not_have_types_field);
}
}
}
else {
if (state.traceEnabled) {
trace(state.host, Diagnostics.File_0_does_not_exist, packageJsonPath);
}
// record package json as one of failed lookup locations - in the future if this file will appear it will invalidate resolution results
failedLookupLocation.push(packageJsonPath);
}
return loadModuleFromFile(combinePaths(candidate, "index"), extensions, failedLookupLocation, !directoryExists, state);
}
function pathToPackageJson(directory: string): string {
return combinePaths(directory, "package.json");
}
function loadModuleFromNodeModulesFolder(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): string {
const nodeModulesFolder = combinePaths(directory, "node_modules");
const nodeModulesFolderExists = directoryProbablyExists(nodeModulesFolder, state.host);
const candidate = normalizePath(combinePaths(nodeModulesFolder, moduleName));
const supportedExtensions = getSupportedExtensions(state.compilerOptions);
let result = loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, !nodeModulesFolderExists, state);
if (result) {
return result;
}
result = loadNodeModuleFromDirectory(supportedExtensions, candidate, failedLookupLocations, !nodeModulesFolderExists, state);
if (result) {
return result;
}
}
/* @internal */
export function loadModuleFromNodeModules(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean): string {
return loadModuleFromNodeModulesWorker(moduleName, directory, failedLookupLocations, state, checkOneLevel, /*typesOnly*/ false);
}
function loadModuleFromNodeModulesAtTypes(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState): string {
return loadModuleFromNodeModulesWorker(moduleName, directory, failedLookupLocations, state, /*checkOneLevel*/ false, /*typesOnly*/ true);
}
function loadModuleFromNodeModulesWorker(moduleName: string, directory: string, failedLookupLocations: string[], state: ModuleResolutionState, checkOneLevel: boolean, typesOnly: boolean): string {
directory = normalizeSlashes(directory);
while (true) {
const baseName = getBaseFileName(directory);
if (baseName !== "node_modules") {
let packageResult: string | undefined;
if (!typesOnly) {
// Try to load source from the package
packageResult = loadModuleFromNodeModulesFolder(moduleName, directory, failedLookupLocations, state);
if (packageResult && hasTypeScriptFileExtension(packageResult)) {
// Always prefer a TypeScript (.ts, .tsx, .d.ts) file shipped with the package
return packageResult;
}
}
// Else prefer a types package over non-TypeScript results (e.g. JavaScript files)
const typesResult = loadModuleFromNodeModulesFolder(combinePaths("@types", moduleName), directory, failedLookupLocations, state);
if (typesResult || packageResult) {
return typesResult || packageResult;
}
}
const parentPath = getDirectoryPath(directory);
if (parentPath === directory || checkOneLevel) {
break;
}
directory = parentPath;
}
return undefined;
}
export function classicNameResolver(moduleName: string, containingFile: string, compilerOptions: CompilerOptions, host: ModuleResolutionHost): ResolvedModuleWithFailedLookupLocations {
const traceEnabled = isTraceEnabled(compilerOptions, host);
const state = { compilerOptions, host, traceEnabled, skipTsx: !compilerOptions.jsx };
const failedLookupLocations: string[] = [];
const supportedExtensions = getSupportedExtensions(compilerOptions);
const containingDirectory = getDirectoryPath(containingFile);
const resolvedFileName = tryLoadModuleUsingOptionalResolutionSettings(moduleName, containingDirectory, loadModuleFromFile, failedLookupLocations, supportedExtensions, state);
if (resolvedFileName) {
return createResolvedModule(resolvedFileName, /*isExternalLibraryImport*/false, failedLookupLocations);
}
let referencedSourceFile: string;
if (moduleHasNonRelativeName(moduleName)) {
referencedSourceFile = referencedSourceFile = loadModuleFromAncestorDirectories(moduleName, containingDirectory, supportedExtensions, failedLookupLocations, state) ||
// If we didn't find the file normally, look it up in @types.
loadModuleFromNodeModulesAtTypes(moduleName, containingDirectory, failedLookupLocations, state);
}
else {
const candidate = normalizePath(combinePaths(containingDirectory, moduleName));
referencedSourceFile = loadModuleFromFile(candidate, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
}
return referencedSourceFile
? { resolvedModule: { resolvedFileName: referencedSourceFile }, failedLookupLocations }
: { resolvedModule: undefined, failedLookupLocations };
}
/** Climb up parent directories looking for a module. */
function loadModuleFromAncestorDirectories(moduleName: string, containingDirectory: string, supportedExtensions: string[], failedLookupLocations: string[], state: ModuleResolutionState): string | undefined {
while (true) {
const searchName = normalizePath(combinePaths(containingDirectory, moduleName));
const referencedSourceFile = loadModuleFromFile(searchName, supportedExtensions, failedLookupLocations, /*onlyRecordFailures*/ false, state);
if (referencedSourceFile) {
return referencedSourceFile;
}
const parentPath = getDirectoryPath(containingDirectory);
if (parentPath === containingDirectory) {
return undefined;
}
containingDirectory = parentPath;
}
}
}