Fixed issue with unknown extension when using allowArbitraryExtensions compiler option

src/compile-dts.ts

@@ -10,7 +10,7 @@ export interface CompileDtsResult {
 	rootFilesRemapping: Map<string, string>;
 }
 
-const declarationExtsRemapping: Record<string, ts.Extension> = {
+const declarationExtsRemapping: Partial<Record<string, ts.Extension>> = {
 	[ts.Extension.Js]: ts.Extension.Js,
 	[ts.Extension.Jsx]: ts.Extension.Jsx,
 	[ts.Extension.Json]: ts.Extension.Json,
@@ -65,6 +65,10 @@ export function compileDts(rootFiles: readonly string[], preferredConfigPath?: s
 			const resolvedModule = ts.resolveModuleName(moduleLiteral.text, containingFile, compilerOptions, host, moduleResolutionCache).resolvedModule;
 			if (resolvedModule && !resolvedModule.isExternalLibraryImport) {
 				const newExt = declarationExtsRemapping[resolvedModule.extension];
+				if (newExt === undefined) {
+					verboseLog(`Skipping module ${resolvedModule.resolvedFileName} because it has unsupported extension "${resolvedModule.extension}"`);
+					return { resolvedModule };
+				}
 
 				// eslint-disable-next-line @typescript-eslint/no-unsafe-enum-comparison
 				if (newExt !== resolvedModule.extension) {

tests/e2e/test-cases/allow-arbitrary-extensions/config.ts

@@ -0,0 +1,5 @@
+import { TestCaseConfig } from '../../test-cases/test-case-config';
+
+const config: TestCaseConfig = {};
+
+export = config;

tests/e2e/test-cases/allow-arbitrary-extensions/hello.d.json.ts

@@ -0,0 +1,3 @@
+declare const hello: Record<any, any>;
+
+export default hello;

tests/e2e/test-cases/allow-arbitrary-extensions/hello.json

@@ -0,0 +1,3 @@
+{
+  "test": 1
+}

tests/e2e/test-cases/allow-arbitrary-extensions/index.spec.js

@@ -0,0 +1 @@
+require('../run-test-case').runTestCase(__dirname);

tests/e2e/test-cases/allow-arbitrary-extensions/input.d.ts

@@ -0,0 +1,3 @@
+import hello from './hello.json';
+
+export function test(): typeof hello;

tests/e2e/test-cases/allow-arbitrary-extensions/output.d.ts

@@ -0,0 +1,4 @@
+declare const hello: Record<any, any>;
+export function test(): typeof hello;
+
+export {};

tests/e2e/test-cases/allow-arbitrary-extensions/tsconfig.json

@@ -0,0 +1,8 @@
+{
+	"extends": "../tsconfig.json",
+	"compilerOptions": {
+		"allowArbitraryExtensions": true,
+		"esModuleInterop": true,
+		"resolveJsonModule": true
+	}
+}