refactor: minor improvements

.github/workflows/ci.yml

@@ -6,7 +6,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        node: [16, 18, 20]
+        node: [16, 18, 20, 22]
         os: [ubuntu-latest, windows-latest]
 
     name: Node ${{ matrix.node }} on ${{ matrix.os }}

rollup.config.ts

@@ -3,7 +3,7 @@ import type { RollupWatchOptions } from "rollup";
 import dts from "./src/index.js";
 
 const pkg = JSON.parse(fs.readFileSync("./package.json", { encoding: "utf-8" }));
-const external = ["module", "path", "typescript", "rollup", "@babel/code-frame", "magic-string"];
+const external = ["node:module", "node:path", "typescript", "rollup", "@babel/code-frame", "magic-string"];
 
 const config: Array<RollupWatchOptions> = [
   {

src/index.ts

@@ -1,4 +1,4 @@
-import * as path from "path";
+import * as path from "node:path";
 import type { PluginImpl, Plugin } from "rollup";
 import ts from "typescript";
 import { type Options, resolveDefaultOptions, type ResolvedOptions } from "./options.js";
@@ -140,7 +140,7 @@ const plugin: PluginImpl<Options> = (options = {}) => {
 
       const treatTsAsDts = () => {
         const declarationId = id.replace(TS_EXTENSIONS, dts);
-        let module = getModule(ctx, declarationId, code);
+        const module = getModule(ctx, declarationId, code);
         if (module) {
           watchFiles(module);
           return transformPlugin.transform.call(this, module.code, declarationId);

src/options.ts

@@ -1,4 +1,4 @@
-import ts from "typescript";
+import type ts from "typescript";
 
 export interface Options {
   /**

src/program.ts

@@ -1,4 +1,4 @@
-import * as path from "path";
+import * as path from "node:path";
 import ts from "typescript";
 
 export const DTS_EXTENSIONS = /\.d\.(c|m)?tsx?$/;
@@ -30,7 +30,7 @@ const DEFAULT_OPTIONS: ts.CompilerOptions = {
 
 const configByPath = new Map<string, ts.ParsedCommandLine>();
 
-const logCache = (...args: any[]) => (process.env.DTS_LOG_CACHE ? console.log("[cache]", ...args) : null);
+const logCache = (...args: unknown[]) => (process.env.DTS_LOG_CACHE ? console.log("[cache]", ...args) : null);
 
 /**
  * Caches the config for every path between two given paths.
@@ -71,7 +71,7 @@ export function getCompilerOptions(
     if (!configPath) {
       return { dtsFiles, dirName, compilerOptions };
     }
-    let inputDirName = dirName;
+    const inputDirName = dirName;
     dirName = path.dirname(configPath);
     const { config, error } = ts.readConfigFile(configPath, ts.sys.readFile);
     if (error) {
@@ -118,8 +118,8 @@ export function createProgram(fileName: string, overrideOptions: ts.CompilerOpti
 
 export function createPrograms(input: Array<string>, overrideOptions: ts.CompilerOptions, tsconfig?: string) {
   const programs = [];
+  const dtsFiles: Set<string> = new Set();
   let inputs: Array<string> = [];
-  let dtsFiles: Set<string> = new Set();
   let dirName = "";
   let compilerOptions: ts.CompilerOptions = {};
 

src/transform/DeclarationScope.ts

@@ -129,7 +129,7 @@ export class DeclarationScope {
       throw new UnsupportedSyntaxError(node.name);
     }
 
-    let object = ts.isIdentifier(node.expression)
+    const object = ts.isIdentifier(node.expression)
       ? createIdentifier(node.expression)
       : this.convertPropertyAccess(node.expression);
 
@@ -190,7 +190,7 @@ export class DeclarationScope {
     }
   }
 
-  convertMembers(members: ts.NodeArray<ts.TypeElement | ts.ClassElement>) {
+  convertMembers(members: ts.NodeArray<ts.TypeElement | ts.ClassElement>): void {
     for (const node of members) {
       if (ts.isPropertyDeclaration(node) || ts.isPropertySignature(node) || ts.isIndexSignatureDeclaration(node)) {
         if (ts.isPropertyDeclaration(node) && node.initializer && ts.isPropertyAccessExpression(node.initializer)) {
@@ -229,7 +229,7 @@ export class DeclarationScope {
     return params.length;
   }
 
-  convertTypeNode(node?: ts.TypeNode): any {
+  convertTypeNode(node?: ts.TypeNode): void {
     if (!node) {
       return;
     }
@@ -242,11 +242,13 @@ export class DeclarationScope {
       return;
     }
     if (ts.isTypeLiteralNode(node)) {
-      return this.convertMembers(node.members);
+      this.convertMembers(node.members);
+      return
     }
 
     if (ts.isArrayTypeNode(node)) {
-      return this.convertTypeNode(node.elementType);
+      this.convertTypeNode(node.elementType);
+      return
     }
     if (ts.isTupleTypeNode(node)) {
       for (const type of node.elements) {
@@ -260,7 +262,8 @@ export class DeclarationScope {
       ts.isTypeOperatorNode(node) ||
       ts.isTypePredicateNode(node)
     ) {
-      return this.convertTypeNode(node.type);
+      this.convertTypeNode(node.type);
+      return
     }
     if (ts.isUnionTypeNode(node) || ts.isIntersectionTypeNode(node)) {
       for (const type of node.types) {
@@ -353,7 +356,7 @@ export class DeclarationScope {
         if (stmt.name && ts.isIdentifier(stmt.name)) {
           this.pushTypeVariable(stmt.name);
         } else {
-          throw new UnsupportedSyntaxError(stmt, `non-Identifier name not supported`);
+          throw new UnsupportedSyntaxError(stmt, 'non-Identifier name not supported');
         }
         continue;
       }
@@ -362,15 +365,15 @@ export class DeclarationScope {
           if (ts.isIdentifier(decl.name)) {
             this.pushTypeVariable(decl.name);
           } else {
-            throw new UnsupportedSyntaxError(decl, `non-Identifier name not supported`);
+            throw new UnsupportedSyntaxError(decl, 'non-Identifier name not supported');
           }
         }
         continue;
       }
       if (ts.isExportDeclaration(stmt)) {
         // noop
       } else {
-        throw new UnsupportedSyntaxError(stmt, `namespace child (hoisting) not supported yet`);
+        throw new UnsupportedSyntaxError(stmt, 'namespace child (hoisting) not supported yet');
       }
     }
 
@@ -420,7 +423,7 @@ export class DeclarationScope {
           }
         }
       } else {
-        throw new UnsupportedSyntaxError(stmt, `namespace child (walking) not supported yet`);
+        throw new UnsupportedSyntaxError(stmt, 'namespace child (walking) not supported yet');
       }
     }
 

src/transform/NamespaceFixer.ts

@@ -70,10 +70,10 @@ export class NamespaceFixer {
         node.moduleSpecifier &&
         ts.isStringLiteral(node.moduleSpecifier)
       ) {
-        let { text } = node.moduleSpecifier;
+        const { text } = node.moduleSpecifier;
         if (text.startsWith(".") && (text.endsWith(".d.ts") || text.endsWith(".d.cts") || text.endsWith(".d.mts"))) {
-          let start = node.moduleSpecifier.getStart() + 1; // +1 to account for the quote
-          let end = node.moduleSpecifier.getEnd() - 1; // -1 to account for the quote
+          const start = node.moduleSpecifier.getStart() + 1; // +1 to account for the quote
+          const end = node.moduleSpecifier.getEnd() - 1; // -1 to account for the quote
           namespaces.unshift({
             name: "",
             exports: [],

src/transform/Transformer.ts

@@ -61,7 +61,7 @@ class Transformer {
 
       // we possibly have other declarations, such as an ExportDeclaration in
       // between, which should also be updated to the correct start/end.
-      let selfIdx = this.ast.body.findIndex((node) => node == existingScope.declaration);
+      const selfIdx = this.ast.body.findIndex((node) => node == existingScope.declaration);
       for (let i = selfIdx + 1; i < this.ast.body.length; i++) {
         const decl = this.ast.body[i] as any;
         decl.start = decl.end = range.end;
@@ -95,7 +95,7 @@ class Transformer {
     if (ts.isModuleDeclaration(node)) {
       return this.convertNamespaceDeclaration(node);
     }
-    if (node.kind == ts.SyntaxKind.NamespaceExportDeclaration) {
+    if (node.kind === ts.SyntaxKind.NamespaceExportDeclaration) {
       // just ignore `export as namespace FOO` statements…
       return this.removeStatement(node);
     }
@@ -143,7 +143,7 @@ class Transformer {
 
   convertFunctionDeclaration(node: ts.FunctionDeclaration) {
     if (!node.name) {
-      throw new UnsupportedSyntaxError(node, `FunctionDeclaration should have a name`);
+      throw new UnsupportedSyntaxError(node, 'FunctionDeclaration should have a name');
     }
 
     const scope = this.createDeclaration(node, node.name);
@@ -153,7 +153,7 @@ class Transformer {
 
   convertClassOrInterfaceDeclaration(node: ts.ClassDeclaration | ts.InterfaceDeclaration) {
     if (!node.name) {
-      throw new UnsupportedSyntaxError(node, `ClassDeclaration / InterfaceDeclaration should have a name`);
+      throw new UnsupportedSyntaxError(node, 'ClassDeclaration / InterfaceDeclaration should have a name');
     }
 
     const scope = this.createDeclaration(node, node.name);
@@ -175,11 +175,11 @@ class Transformer {
   convertVariableStatement(node: ts.VariableStatement) {
     const { declarations } = node.declarationList;
     if (declarations.length !== 1) {
-      throw new UnsupportedSyntaxError(node, `VariableStatement with more than one declaration not yet supported`);
+      throw new UnsupportedSyntaxError(node, 'VariableStatement with more than one declaration not yet supported');
     }
     for (const decl of declarations) {
       if (!ts.isIdentifier(decl.name)) {
-        throw new UnsupportedSyntaxError(node, `VariableDeclaration must have a name`);
+        throw new UnsupportedSyntaxError(node, 'VariableDeclaration must have a name');
       }
 
       const scope = this.createDeclaration(node, decl.name);

src/transform/astHelpers.ts

@@ -153,7 +153,7 @@ export interface Range {
 }
 
 export function withStartEnd<T extends ESTree.Node>(esNode: T, nodeOrRange: ts.Node | Range): T {
-  let range: Range =
+  const range: Range =
     "start" in nodeOrRange ? nodeOrRange : { start: nodeOrRange.getStart(), end: nodeOrRange.getEnd() };
   return Object.assign(esNode, range);
 }

src/transform/errors.ts

@@ -1,6 +1,6 @@
-import * as codeFrame from "@babel/code-frame";
-import ts from "typescript";
-import { createRequire } from "module";
+import { createRequire } from "node:module";
+import type * as codeFrame from "@babel/code-frame";
+import type ts from "typescript";
 
 function getCodeFrame(): typeof codeFrame.codeFrameColumns | undefined {
   let codeFrameColumns = undefined;

src/transform/index.ts

@@ -1,4 +1,4 @@
-import * as path from "path";
+import * as path from "node:path";
 import type { Plugin } from "rollup";
 import ts from "typescript";
 import { NamespaceFixer } from "./NamespaceFixer.js";
@@ -39,7 +39,7 @@ export const transform = () => {
       return {
         ...options,
         onLog(level, log, defaultHandler) {
-          if (level === "warn" && log.code == "CIRCULAR_DEPENDENCY") {
+          if (level === "warn" && log.code === "CIRCULAR_DEPENDENCY") {
             return;
           }
           if (onLog) {

src/transform/preprocess.ts

@@ -108,7 +108,7 @@ export function preProcess({ sourceFile }: PreProcessInput): PreProcessOutput {
       fixModifiers(code, node);
 
       // collect the ranges for re-ordering
-      if (declarations.length == 1) {
+      if (declarations.length === 1) {
         const decl = declarations[0]!;
         if (ts.isIdentifier(decl.name)) {
           pushNamedNode(decl.name.getText(), [getStart(node), getEnd(node)]);
@@ -143,7 +143,7 @@ export function preProcess({ sourceFile }: PreProcessInput): PreProcessOutput {
           code.appendLeft(commaPos, ";\n");
           const start = node.getFullStart();
           const slice = code.slice(start, node.getStart());
-          let whitespace = slice.length - slice.trimStart().length;
+          const whitespace = slice.length - slice.trimStart().length;
           if (whitespace) {
             code.overwrite(start, start + whitespace, prefix);
           } else {
@@ -230,7 +230,7 @@ export function preProcess({ sourceFile }: PreProcessInput): PreProcessOutput {
     const { line } = sourceFile.getLineAndCharacterOfPosition(ref.pos);
     const start = lineStarts[line]!;
     let end = sourceFile.getLineEndOfPosition(ref.pos);
-    if (code.slice(end, end + 1) == "\n") {
+    if (code.slice(end, end + 1) === "\n") {
       end += 1;
     }
 
@@ -245,7 +245,7 @@ export function preProcess({ sourceFile }: PreProcessInput): PreProcessOutput {
     const { line } = sourceFile.getLineAndCharacterOfPosition(ref.pos);
     const start = lineStarts[line]!;
     let end = sourceFile.getLineEndOfPosition(ref.pos);
-    if (code.slice(end, end + 1) == "\n") {
+    if (code.slice(end, end + 1) === "\n") {
       end += 1;
     }
 
@@ -371,5 +371,5 @@ function getEnd(node: ts.Node): number {
 }
 
 function newlineAt(node: ts.Node, idx: number): boolean {
-  return node.getSourceFile().getFullText()[idx] == "\n";
+  return node.getSourceFile().getFullText()[idx] === "\n";
 }