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feat(resolve)!: support "exports" field
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@AviVahl
AviVahl committed Jul 31, 2023
1 parent c06069c commit ea64f94
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Showing 4 changed files with 545 additions and 80 deletions.
6 changes: 3 additions & 3 deletions packages/commonjs/test/npm-packages.nodespec.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ describe('commonjs module system - integration with existing npm packages', func
it('evaluates postcss successfully', () => {
const { requireFrom, requireCache } = createCjsModuleSystem({
fs,
resolver: createRequestResolver({ fs, target: 'node' }),
resolver: createRequestResolver({ fs, conditions: ['node', 'require'] }),
});
requireCache.set('path', { filename: 'path', id: 'path', exports: path, children: [] });
requireCache.set('url', { filename: 'url', id: 'url', exports: url, children: [] });
Expand All @@ -60,7 +60,7 @@ describe('commonjs module system - integration with existing npm packages', func
it('evaluates mocha successfully', () => {
const { requireFrom, requireCache } = createCjsModuleSystem({
fs,
resolver: createRequestResolver({ fs, target: 'node' }),
resolver: createRequestResolver({ fs, conditions: ['node', 'require'] }),
});
requireCache.set('path', { filename: 'path', id: 'path', exports: path, children: [] });
requireCache.set('stream', { filename: 'stream', id: 'stream', exports: stream, children: [] });
Expand All @@ -77,7 +77,7 @@ describe('commonjs module system - integration with existing npm packages', func
it('evaluates sass successfully', () => {
const { requireFrom, requireCache } = createCjsModuleSystem({
fs,
resolver: createRequestResolver({ fs, target: 'node' }),
resolver: createRequestResolver({ fs, conditions: ['node', 'require'] }),
});
requireCache.set('fs', { filename: 'fs', id: 'fs', exports: fs, children: [] });
requireCache.set('path', { filename: 'path', id: 'path', exports: path, children: [] });
Expand Down
163 changes: 154 additions & 9 deletions packages/resolve/src/request-resolver.ts
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Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
import type { PackageJson } from 'type-fest';
import type { RequestResolver, IRequestResolverOptions, IResolvedPackageJson, IResolutionOutput } from './types.js';
import type { IRequestResolverOptions, IResolutionOutput, IResolvedPackageJson, RequestResolver } from './types.js';

const defaultTarget = 'browser';
const defaultPackageRoots = ['node_modules'];
const defaultExtensions = ['.js', '.json'];
const defaultConditions = ['browser', 'import', 'require'];
const isRelative = (request: string) =>
request === '.' || request === '..' || request.startsWith('./') || request.startsWith('../');
const PACKAGE_JSON = 'package.json';
Expand All @@ -14,13 +14,16 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
fs: { statSync, readFileSync, realpathSync, dirname, join, resolve, isAbsolute },
packageRoots = defaultPackageRoots,
extensions = defaultExtensions,
target = defaultTarget,
moduleField = target === 'browser',
conditions = defaultConditions,
resolvedPacakgesCache = new Map<string, IResolvedPackageJson | undefined>(),
alias = {},
fallback = {},
} = options;

const exportConditions = new Set(conditions);
const targetsBrowser = exportConditions.has('browser');
const targetsEsm = exportConditions.has('import');

const loadPackageJsonFromCached = wrapWithCache(loadPackageJsonFrom, resolvedPacakgesCache);
const remapUsingAlias = createRequestRemapper(alias);
const remapUsingFallback = createRequestRemapper(fallback);
Expand All @@ -39,7 +42,7 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
if (!statSyncSafe(resolvedFilePath)?.isFile()) {
continue;
}
if (target === 'browser') {
if (targetsBrowser) {
const toPackageJson = findUpPackageJson(dirname(resolvedFilePath));
if (toPackageJson) {
visitedPaths.add(toPackageJson.filePath);
Expand Down Expand Up @@ -73,7 +76,7 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
yield requestAlias;
}

if (!emittedCandidate && target === 'browser') {
if (!emittedCandidate && targetsBrowser) {
const fromPackageJson = findUpPackageJson(contextPath);
if (fromPackageJson) {
visitedPaths.add(fromPackageJson.filePath);
Expand Down Expand Up @@ -133,6 +136,7 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
if (resolvedPackageJson !== undefined) {
visitedPaths.add(resolvedPackageJson.filePath);
}

const mainPath = resolvedPackageJson?.mainPath;

if (mainPath !== undefined) {
Expand All @@ -147,6 +151,27 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
if (!statSyncSafe(packagesPath)?.isDirectory()) {
continue;
}
const [packageName, innerPath] = parsePackageSpecifier(request);
if (!packageName.length || (packageName.startsWith('@') && !packageName.includes('/'))) {
return;
}
const packageDirectoryPath = join(packagesPath, packageName);
const resolvedPackageJson = loadPackageJsonFromCached(packageDirectoryPath);
if (resolvedPackageJson !== undefined) {
visitedPaths.add(resolvedPackageJson.filePath);
}
if (resolvedPackageJson?.exports !== undefined) {
const exactMatchExports = resolvedPackageJson.exports[innerPath];
if (exactMatchExports !== undefined) {
yield* resolveExportConditions(packageDirectoryPath, exactMatchExports);
} else if (resolvedPackageJson.hasPatternExports) {
const matchedPattern = matchSubpathPatterns(resolvedPackageJson.exports, innerPath);
if (matchedPattern !== undefined) {
yield join(packageDirectoryPath, matchedPattern);
}
}
return;
}
const requestInPackages = join(packagesPath, request);
yield* fileRequestPaths(requestInPackages);
yield* directoryRequestPaths(requestInPackages, visitedPaths);
Expand Down Expand Up @@ -181,7 +206,7 @@ export function createRequestResolver(options: IRequestResolverOptions): Request

const { browser } = packageJson;
let browserMappings: Record<string, string | false> | undefined = undefined;
if (target === 'browser' && typeof browser === 'object' && browser !== null) {
if (targetsBrowser && typeof browser === 'object' && browser !== null) {
browserMappings = Object.create(null) as Record<string, string | false>;
for (const [from, to] of Object.entries(browser)) {
const resolvedFrom = isRelative(from) ? resolveRelative(join(directoryPath, from)) : from;
Expand All @@ -194,14 +219,38 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
}
}

const [desugerifiedExports, hasPatternExports] = desugarifyExportsField(packageJson.exports);

return {
filePath: packageJsonPath,
directoryPath,
mainPath,
browserMappings,
exports: desugerifiedExports,
hasPatternExports,
};
}

function* resolveExportConditions(directoryPath: string, exportedValue: PackageJson.Exports): Generator<string> {
if (exportedValue === null) {
return;
} else if (typeof exportedValue === 'string') {
yield join(directoryPath, exportedValue);
} else if (typeof exportedValue === 'object') {
if (Array.isArray(exportedValue)) {
for (const arrayItem of exportedValue) {
yield* resolveExportConditions(directoryPath, arrayItem);
}
} else {
for (const [key, value] of Object.entries(exportedValue)) {
if (key === 'default' || exportConditions.has(key)) {
yield* resolveExportConditions(directoryPath, value);
}
}
}
}
}

function resolveRemappedRequest(directoryPath: string, to: string | false): string | false | undefined {
if (to === false) {
return to;
Expand Down Expand Up @@ -249,14 +298,20 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
}

function packageJsonTarget({ main, browser, module: moduleFieldValue }: PackageJson): string | undefined {
if (target === 'browser' && typeof browser === 'string') {
if (targetsBrowser && typeof browser === 'string') {
return browser;
} else if (moduleField && typeof moduleFieldValue === 'string') {
} else if (targetsEsm && typeof moduleFieldValue === 'string') {
return moduleFieldValue;
}
return typeof main === 'string' ? main : undefined;
}

/**
* Generates a path chain from the current path to the root directory.
*
* @param currentPath The current path to start the chain from.
* @yields The current path and continues to yield the parent directory path until the root directory is reached.
*/
function* pathChainToRoot(currentPath: string) {
let lastPath: string | undefined;
while (lastPath !== currentPath) {
Expand All @@ -279,6 +334,37 @@ export function createRequestResolver(options: IRequestResolverOptions): Request
}
}

function matchSubpathPatterns(exportedSubpaths: PackageJson.ExportConditions, innerPath: string): string | undefined {
let matchedPattern: string | undefined;
for (const [patternKey, patternValue] of Object.entries(exportedSubpaths)) {
const keyStarIdx = patternKey.indexOf('*');
if (keyStarIdx === -1 || patternKey.indexOf('*', keyStarIdx + 1) !== -1) {
continue;
}
const keyPrefix = patternKey.slice(0, keyStarIdx);
if (!innerPath.startsWith(keyPrefix)) {
continue;
}
const keySuffix = patternKey.slice(keyStarIdx + 1);
if (keySuffix && !innerPath.endsWith(keySuffix)) {
continue;
}
if (patternValue === null) {
return undefined;
} else if (typeof patternValue === 'string') {
const keyStarValue = innerPath.slice(keyPrefix.length, -keySuffix.length);
const valueStarIdx = patternValue.indexOf('*');
if (valueStarIdx === -1 || patternValue.indexOf('*', valueStarIdx + 1) !== -1) {
continue;
}
const valuePrefix = patternValue.slice(0, valueStarIdx);
const valueSuffix = patternValue.slice(valueStarIdx + 1);
matchedPattern = valuePrefix + keyStarValue + valueSuffix;
}
}
return matchedPattern;
}

function wrapWithCache<K, T>(fn: (key: K) => T, cache = new Map<K, T>()): (key: K) => T {
return (key: K) => {
if (cache.has(key)) {
Expand Down Expand Up @@ -345,3 +431,62 @@ interface TracedErrorConstructor extends ErrorConstructor {
stackTraceLimit?: number;
}
declare let Error: TracedErrorConstructor;

/**
* Parse a package specifier into a tuple of package name and path in package.
* Handles both scoped and non-scoped package specifiers and returns a default path of '.' if no path is specified.
*
* @param specifier - The package specifier to parse.
* @example parsePackageSpecifier('react-dom') === ['react-dom', "."]
* @example parsePackageSpecifier('react-dom/client') === ['react-dom', './client']
* @example parsePackageSpecifier('@stylable/core') === ['@stylable/core', "./core"]
* @example parsePackageSpecifier('@stylable/core/dist/some-file') === ['@stylable/core', './dist/some-file']
*/
function parsePackageSpecifier(specifier: string): readonly [packageName: string, pathInPackage: string] {
const firstSlashIdx = specifier.indexOf('/');
if (firstSlashIdx === -1) {
return [specifier, '.'];
}
const isScopedPackage = specifier.startsWith('@');
if (isScopedPackage) {
const secondSlashIdx = specifier.indexOf('/', firstSlashIdx + 1);
return secondSlashIdx === -1
? [specifier, '.']
: [specifier.slice(0, secondSlashIdx), '.' + specifier.slice(secondSlashIdx)];
} else {
return [specifier.slice(0, firstSlashIdx), '.' + specifier.slice(firstSlashIdx)];
}
}

/**
* Desugarify the `exports` field of a package.json file.
*
* If `exports` is a string or an array, it is converted to an object with a single key of `'.'`.
* If `exports` is already an object and has a key of `'.'` or starts with `'./'`, it is returned as is.
* Otherwise, `exports` is wrapped in an object with a single key of `'.'`.
*
* @param packageExports - The `exports` field of a package.json file.
* @returns tuple containing the desugarified `exports` field, with a flag saying whether it includes pattern exports.
*/
function desugarifyExportsField(
packageExports: PackageJson.Exports | undefined
): [PackageJson.ExportConditions | undefined, boolean] {
let hasPatternExports = false;
if (packageExports === undefined || packageExports === null) {
packageExports = undefined;
} else if (typeof packageExports === 'string' || Array.isArray(packageExports)) {
packageExports = { '.': packageExports };
} else {
for (const key of Object.keys(packageExports)) {
if (key.includes('*')) {
hasPatternExports = true;
}
if (key !== '.' && !key.startsWith('./')) {
packageExports = { '.': packageExports };
hasPatternExports = false;
break;
}
}
}
return [packageExports, hasPatternExports];
}
19 changes: 9 additions & 10 deletions packages/resolve/src/types.ts
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Original file line number Diff line number Diff line change
@@ -1,3 +1,5 @@
import { PackageJson } from 'type-fest';

export interface IRequestResolverOptions {
/**
* File system to use when resolving requests.
Expand All @@ -19,10 +21,12 @@ export interface IRequestResolverOptions {
extensions?: string[];

/**
* Whether to prefer the 'browser' field or 'main' field
* in `package.json`.
* Package export conditions to try resolving the request with.
*
* @default ['browser', 'import', 'require']
* @see https://nodejs.org/api/packages.html#conditional-exports
*/
target?: 'node' | 'browser';
conditions?: string[];

/**
* Cache for resolved packages. Map keys are directoryPaths.
Expand All @@ -43,13 +47,6 @@ export interface IRequestResolverOptions {
* Original request is attempted before fallback.
*/
fallback?: Record<string, string | false>;

/**
* Support the "module" field. Picked up over "main".
*
* @default true when "target" is set to "browser"
*/
moduleField?: boolean;
}

export interface IResolutionOutput {
Expand Down Expand Up @@ -105,4 +102,6 @@ export interface IResolvedPackageJson {
browserMappings?: {
[from: string]: string | false;
};
exports?: PackageJson.ExportConditions;
hasPatternExports?: boolean;
}
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