Include declaration files when resolving import specifiers

fixtures/dts/package.json

@@ -0,0 +1,3 @@
+{
+  "name": "@fixtures/dts"
+}

fixtures/dts/src/assets.d.ts

@@ -0,0 +1 @@
+declare module '*.html?raw';

fixtures/dts/src/block.html

@@ -0,0 +1 @@
+<div>content</div>

fixtures/dts/src/index.ts

@@ -0,0 +1,4 @@
+import b from './block.html?raw';
+import n from './normal';
+
+console.log(b, n);

fixtures/dts/src/normal.ts

@@ -0,0 +1 @@
+export default 1;

fixtures/dts/tsconfig.json

@@ -0,0 +1,6 @@
+{
+  "include": ["./src/assets.d.ts", "./src"],
+  "compilerOptions": {
+    "skipLibCheck": true
+  }
+}

src/ProjectPrincipal.ts

@@ -27,7 +27,6 @@ const baseCompilerOptions = {
   esModuleInterop: true,
   skipDefaultLibCheck: true,
   skipLibCheck: true,
-  lib: [],
   target: ts.ScriptTarget.Latest,
   module: ts.ModuleKind.CommonJS,
   moduleResolution: ts.ModuleResolutionKind.NodeNext,

src/index.ts

@@ -132,10 +132,13 @@ export const main = async (unresolvedConfiguration: CommandLineOptions) => {
 
     deputy.addWorkspace({ name, dir, manifestPath, manifest, ignoreDependencies, ignoreBinaries });
 
-    const compilerOptions = await loadCompilerOptions(join(dir, tsConfigFile ?? 'tsconfig.json'));
+    const { compilerOptions, definitionPaths } = await loadCompilerOptions(join(dir, tsConfigFile ?? 'tsconfig.json'));
 
     const principal = factory.getPrincipal({ cwd: dir, paths, compilerOptions, compilers });
 
+    // Pushing declaration files to the program as source files seems not enough
+    principal.addEntryPaths(definitionPaths);
+
     const worker = new WorkspaceWorker({
       name,
       dir,

src/plugins/typescript/index.ts

@@ -5,7 +5,6 @@ import { hasDependency, load } from '../../util/plugin.js';
 import { loadTSConfig } from '../../util/tsconfig-loader.js';
 import type { IsPluginEnabledCallback, GenericPluginCallback } from '../../types/plugins.js';
 import type { TsConfigJson } from 'type-fest';
-import type { CompilerOptions } from 'typescript';
 
 // https://www.typescriptlang.org/tsconfig
 
@@ -34,7 +33,7 @@ const resolveExtensibleConfig = async (configFilePath: string) => {
 };
 
 const findTypeScriptDependencies: GenericPluginCallback = async configFilePath => {
-  const compilerOptions: CompilerOptions = await loadTSConfig(configFilePath);
+  const { compilerOptions } = await loadTSConfig(configFilePath);
   const config: TsConfigJson = await resolveExtensibleConfig(configFilePath); // Dual loader to get external `extends` dependencies
 
   if (!compilerOptions || !config) return [];

src/typescript/SourceFileManager.ts

@@ -16,6 +16,7 @@ export class SourceFileManager {
 
   createSourceFile(filePath: string, contents: string) {
     const setParentNodes = isInternal(filePath);
+    // When added explicitly, declaration files are created properly with `.isDeclarationFile: true`
     const sourceFile = ts.createSourceFile(filePath, contents, ts.ScriptTarget.Latest, setParentNodes);
     this.sourceFileCache.set(filePath, sourceFile);
     return sourceFile;

src/typescript/getImportsAndExports.ts

@@ -84,6 +84,7 @@ export const getImportsAndExports = (sourceFile: BoundSourceFile, options: GetIm
     const { specifier, symbol, identifier = '__anonymous', isReExport = false } = options;
     if (isBuiltin(specifier)) return;
 
+    // The specifier exists, but no resolved module
     const module = sourceFile.resolvedModules?.get(specifier, /* mode */ undefined);
 
     if (module?.resolvedModule) {

src/typescript/resolveModuleNames.ts

@@ -11,6 +11,7 @@ export function createCustomModuleResolver(
   }
 
   function resolveModuleName(name: string, containingFile: string): ts.ResolvedModule | undefined {
+    // How to let TypeScript know about the declaration files to resolve e.g. the `*.html?raw` import specifier?
     const tsResolvedModule = ts.resolveModuleName(name, containingFile, compilerOptions, ts.sys).resolvedModule;
 
     if (virtualFileExtensions.length === 0) return tsResolvedModule;

src/util/tsconfig-loader.ts

@@ -6,7 +6,15 @@ export const loadTSConfig = async (tsConfigFilePath: string) => {
   if (isFile(tsConfigFilePath)) {
     const config = ts.readConfigFile(tsConfigFilePath, ts.sys.readFile);
     const parsedConfig = ts.parseJsonConfigFileContent(config.config, ts.sys, dirname(tsConfigFilePath));
-    return parsedConfig.options ?? {};
+    const compilerOptions = parsedConfig.options ?? {};
+
+    // Local declaration files pushed to `lib: []` seem not be taken into account by ts.resolveModuleName()
+    // const definitionPaths = parsedConfig.fileNames.filter(filePath => filePath.endsWith('.d.ts'));
+    // compilerOptions.lib = compilerOptions.lib ?? [];
+    // compilerOptions.lib.push(...definitionPaths);
+    const definitionPaths: string[] = [];
+
+    return { compilerOptions, definitionPaths };
   }
-  return {};
+  return { compilerOptions: {}, definitionPaths: [] };
 };