refactor: strict type checks

.github/workflows/ci.yml

@@ -24,6 +24,8 @@ jobs:
       - run: pnpm install
       - run: pnpm lint
         if: matrix.os == 'ubuntu-latest'
+      - run: test:types
+        if: matrix.os == 'ubuntu-latest'
       - run: pnpm build
         if: matrix.os == 'ubuntu-latest'
       - run: pnpm vitest --coverage

package.json

@@ -23,7 +23,8 @@
     "lint": "eslint --ext .ts,.js src test && prettier -c src test",
     "lint:fix": "eslint --ext .ts,.js src test --fix && prettier -w src test",
     "release": "pnpm test && pnpm build && changelogen --release && npm publish && git push --follow-tags",
-    "test": "pnpm lint && vitest run"
+    "test": "pnpm lint && pnpm test:types && vitest run",
+    "test:types": "tsc --noEmit"
   },
   "dependencies": {
     "acorn": "^8.11.3",
@@ -45,4 +46,4 @@
     "vitest": "^1.2.2"
   },
   "packageManager": "pnpm@8.15.1"
-}
+}

src/_utils.ts

@@ -2,23 +2,23 @@ import { builtinModules } from "node:module";
 
 export const BUILTIN_MODULES = new Set(builtinModules);
 
-export function normalizeSlash(string_) {
-  return string_.replace(/\\/g, "/");
+export function normalizeSlash(path: string): string {
+  return path.replace(/\\/g, "/");
 }
 
-export function isObject(value) {
+export function isObject(value: unknown): boolean {
   return value !== null && typeof value === "object";
 }
 
-export function matchAll(regex, string, addition) {
+export function matchAll(regex: RegExp, string: string, addition: any) {
   const matches = [];
   for (const match of string.matchAll(regex)) {
     matches.push({
       ...addition,
       ...match.groups,
       code: match[0],
       start: match.index,
-      end: match.index + match[0].length,
+      end: (match.index || 0) + match[0].length,
     });
   }
   return matches;

src/analyze.ts

@@ -122,13 +122,13 @@ export function parseStaticImport(
 ): ParsedStaticImport {
   const cleanedImports = clearImports(matched.imports);
 
-  const namedImports = {};
-  for (const namedImport of cleanedImports
-    .match(/{([^}]*)}/)?.[1]
-    ?.split(",") || []) {
-    const [, source = namedImport.trim(), importName = source] =
-      namedImport.match(/^\s*(\S*) as (\S*)\s*$/) || [];
-    if (source && !TYPE_RE.test(source)) {
+  const namedImports: Record<string, string> = {};
+  const _matches = cleanedImports.match(/{([^}]*)}/)?.[1]?.split(",") || [];
+  for (const namedImport of _matches) {
+    const _match = namedImport.match(/^\s*(\S*) as (\S*)\s*$/);
+    const source = _match?.[1] || namedImport.trim();
+    const importName = _match?.[2] || source;
+    if (!TYPE_RE.test(source)) {
       namedImports[source] = importName;
     }
   }
@@ -151,16 +151,14 @@ export function parseTypeImport(
 
   const cleanedImports = clearImports(matched.imports);
 
-  const namedImports = {};
-  for (const namedImport of cleanedImports
-    .match(/{([^}]*)}/)?.[1]
-    ?.split(",") || []) {
-    const [, source = namedImport.trim(), importName = source] = (() => {
-      return /\s+as\s+/.test(namedImport)
-        ? namedImport.match(/^\s*type\s+(\S*) as (\S*)\s*$/) || []
-        : namedImport.match(/^\s*type\s+(\S*)\s*$/) || [];
-    })();
-
+  const namedImports: Record<string, string> = {};
+  const _matches = cleanedImports.match(/{([^}]*)}/)?.[1]?.split(",") || [];
+  for (const namedImport of _matches) {
+    const _match = /\s+as\s+/.test(namedImport)
+      ? namedImport.match(/^\s*type\s+(\S*) as (\S*)\s*$/)
+      : namedImport.match(/^\s*type\s+(\S*)\s*$/);
+    const source = _match?.[1] || namedImport.trim();
+    const importName = _match?.[2] || source;
     if (source && TYPE_RE.test(namedImport)) {
       namedImports[source] = importName;
     }
@@ -326,7 +324,7 @@ function normalizeExports(exports: (ESMExport & { declaration?: string })[]) {
     if (!exp.names && exp.name) {
       exp.names = [exp.name];
     }
-    if (exp.type === "declaration") {
+    if (exp.type === "declaration" && exp.declaration) {
       exp.declarationType = exp.declaration.replace(
         /^declare\s*/,
         "",
@@ -368,14 +366,15 @@ export async function resolveModuleExportNames(
 
   // Recursive * exports
   for (const exp of exports) {
-    if (exp.type === "star") {
-      const subExports = await resolveModuleExportNames(exp.specifier, {
-        ...options,
-        url,
-      });
-      for (const subExport of subExports) {
-        exportNames.add(subExport);
-      }
+    if (exp.type !== "star" || !exp.specifier) {
+      continue;
+    }
+    const subExports = await resolveModuleExportNames(exp.specifier, {
+      ...options,
+      url,
+    });
+    for (const subExport of subExports) {
+      exportNames.add(subExport);
     }
   }
 

src/cjs.ts

@@ -16,14 +16,19 @@ export function createCommonJS(url: string): CommonjsContext {
   const __dirname = dirname(__filename);
 
   // Lazy require
-  let _nativeRequire;
-  const getNativeRequire = () =>
-    _nativeRequire || (_nativeRequire = createRequire(url));
-  function require(id) {
+  let _nativeRequire: typeof require;
+  const getNativeRequire = () => {
+    if (!_nativeRequire) {
+      _nativeRequire = createRequire(url);
+    }
+    return _nativeRequire;
+  };
+  function require(id: string): any {
     return getNativeRequire()(id);
   }
-  require.resolve = (id, options) => getNativeRequire().resolve(id, options);
-
+  require.resolve = function requireResolve(id: string, options: any): string {
+    return getNativeRequire().resolve(id, options);
+  };
   return {
     __filename,
     __dirname,

src/eval.ts

@@ -35,7 +35,7 @@ export async function evalModule(
 
 export function transformModule(
   code: string,
-  options?: EvaluateOptions,
+  options: EvaluateOptions = {},
 ): Promise<string> {
   // Convert JSON to module
   if (options.url && options.url.endsWith(".json")) {

src/resolve.ts

@@ -28,8 +28,8 @@ function _tryModuleResolve(
 ): URL | undefined {
   try {
     return moduleResolve(id, url, conditions);
-  } catch (error) {
-    if (!NOT_FOUND_ERRORS.has(error.code)) {
+  } catch (error: any) {
+    if (!NOT_FOUND_ERRORS.has(error?.code)) {
       throw error;
     }
   }
@@ -66,8 +66,8 @@ function _resolve(id: string | URL, options: ResolveOptions = {}): string {
       if (stat.isFile()) {
         return pathToFileURL(id);
       }
-    } catch (error) {
-      if (error.code !== "ENOENT") {
+    } catch (error: any) {
+      if (error?.code !== "ENOENT") {
         throw error;
       }
     }
@@ -80,10 +80,10 @@ function _resolve(id: string | URL, options: ResolveOptions = {}): string {
 
   // Search paths
   const _urls: URL[] = (
-    Array.isArray(options.url) ? options.url : [options.url]
+    (Array.isArray(options.url) ? options.url : [options.url]) as URL[]
   )
     .filter(Boolean)
-    .map((url) => new URL(normalizeid(url!.toString())));
+    .map((url) => new URL(normalizeid(url.toString())));
   if (_urls.length === 0) {
     _urls.push(new URL(pathToFileURL(process.cwd())));
   }
@@ -226,21 +226,21 @@ function _findSubpath(subpath: string, exports: PackageJson["exports"]) {
     subpath = subpath.startsWith("/") ? `.${subpath}` : `./${subpath}`;
   }
 
-  if (subpath in exports) {
+  if (subpath in (exports || {})) {
     return subpath;
   }
 
   return _flattenExports(exports).find((p) => p.fsPath === subpath)?.subpath;
 }
 
 function _flattenExports(
-  exports: Exclude<PackageJson["exports"], string>,
+  exports: Exclude<PackageJson["exports"], string> = {},
   parentSubpath = "./",
 ): { subpath: string; fsPath: string; condition?: string }[] {
   return Object.entries(exports).flatMap(([key, value]) => {
     const [subpath, condition] = key.startsWith(".")
       ? [key.slice(1), undefined]
-      : [undefined, key];
+      : ["", key];
     const _subPath = joinURL(parentSubpath, subpath);
     // eslint-disable-next-line unicorn/prefer-ternary
     if (typeof value === "string") {

src/syntax.ts

@@ -80,7 +80,7 @@ export async function isValidNodeImport(
   const options = { ...validNodeImportDefaults, ..._options };
 
   const proto = getProtocol(id);
-  if (proto && !options.allowedProtocols.includes(proto)) {
+  if (proto && !options.allowedProtocols?.includes(proto)) {
     return false;
   }
 

src/utils.ts

@@ -71,5 +71,5 @@ const ProtocolRegex = /^(?<proto>.{2,}?):.+$/;
 
 export function getProtocol(id: string): string | undefined {
   const proto = id.match(ProtocolRegex);
-  return proto ? proto.groups.proto : undefined;
+  return proto ? proto.groups?.proto : undefined;
 }

test/imports.test.ts

@@ -9,7 +9,17 @@ import {
 
 // -- Static import --
 
-const staticTests = {
+type MaybeArray<T> = T | T[];
+const staticTests: Record<
+  string,
+  MaybeArray<{
+    specifier: string;
+    defaultImport?: string;
+    namespacedImport?: string;
+    namedImports?: Record<string, string>;
+    type?: string;
+  }>
+> = {
   'import defaultMember from "module-name";': {
     specifier: "module-name",
     defaultImport: "defaultMember",
@@ -188,7 +198,7 @@ const dynamicTests = {
   },
   '// import("abc").then(r => r.default)': [],
   '/* import("abc").then(r => r.default) */': [],
-};
+} as const;
 
 const TypeTests = {
   'import { type Foo, Bar } from "module-name";': {
@@ -276,7 +286,7 @@ describe("findDynamicImports", () => {
       const match = matches[0];
       if (match) {
         expect(match.type).to.equal("dynamic");
-        expect(match.expression.trim()).to.equal(test.expression);
+        expect(match.expression.trim()).to.equal((test as any).expression);
       }
     });
   }

test/utils.test.ts

@@ -20,9 +20,9 @@ describe("isNodeBuiltin", () => {
     "fs/fake": true, // invalid import
   };
 
-  for (const id in cases) {
-    it(`'${id}': ${cases[id]}`, () => {
-      expect(isNodeBuiltin(id)).to.equal(cases[id]);
+  for (const [input, output] of Object.entries(cases)) {
+    it(`'${input}': ${output}`, () => {
+      expect(isNodeBuiltin(input)).to.equal(output);
     });
   }
 
@@ -43,10 +43,10 @@ describe("sanitizeFilePath", () => {
     "Foo.vue&vue&type=script&setup=true&generic=T%20extends%20any%2C%20O%20extends%20T%3CZ%7Ca%3E&lang":
       "Foo.vue_vue_type_script_setup_true_generic_T_extends_any__O_extends_T_Z_a__lang",
     "": "",
-  };
-  for (const id in cases) {
-    it(`'${id}': ${cases[id]}`, () => {
-      expect(sanitizeFilePath(id)).to.equal(cases[id]);
+  } as const;
+  for (const [input, output] of Object.entries(cases)) {
+    it(`'${input}': ${output}`, () => {
+      expect(sanitizeFilePath(input)).to.equal(output);
     });
   }
 

tsconfig.json

@@ -5,10 +5,11 @@
     "moduleResolution": "Node",
     "resolveJsonModule": true,
     "esModuleInterop": true,
-    "checkJs": true,
+    "strict": true,
+    "skipLibCheck": true,
     "paths": {
-      "mlly": ["./"]
+      "mlly": ["./"],
     },
-    "types": ["node"]
-  }
+    "types": ["node"],
+  },
 }