fix(tsconfig): support multiple tsconfigs to be specified

src/loader.ts

@@ -10,22 +10,20 @@
 	parseTsconfig,
 	createFilesMatcher,
 	type TsConfigResult,
-	type FileMatcher,
 } from 'get-tsconfig';
 import type { LoaderOptions } from './types.js';
 
-let foundTsconfig: TsConfigResult | null;
-let fileMatcher: FileMatcher;
+const tsconfigCache = new Map<string, TsConfigResult>();
 
 async function ESBuildLoader(
 	this: webpack.loader.LoaderContext<LoaderOptions>,
 	source: string,
 ): Promise<void> {
 	const done = this.async()!;
 	const options: LoaderOptions = typeof this.getOptions === 'function' ? this.getOptions() : getOptions(this);
 	const {
 		implementation,
-		tsconfig,
+		tsconfig: tsconfigPath,
 		...esbuildTransformOptions
 	} = options;
 
@@ -49,26 +47,44 @@
 	};
 
 	if (!('tsconfigRaw' in transformOptions)) {
-		if (!fileMatcher) {
-			const tsconfigPath = tsconfig && path.resolve(tsconfig);
-			foundTsconfig = (
-				tsconfigPath
-					? {
-						config: parseTsconfig(tsconfigPath),
-						path: tsconfigPath,
-					}
-					: getTsconfig()
-			);
-			if (foundTsconfig) {
-				fileMatcher = createFilesMatcher(foundTsconfig);
+		const { resourcePath } = this;
+		/**
+		 * If a tsconfig.json path is specified, force apply it
+		 * Same way a provided tsconfigRaw is applied regardless
+		 * of whether it actually matches
+		 *
+		 * However in this case, we also warn if it doesn't match
+		 */
+		if (tsconfigPath) {
+			const tsconfigFullPath = path.resolve(tsconfigPath);
+			let tsconfig = tsconfigCache.get(tsconfigFullPath);
+			if (!tsconfig) {
+				tsconfig = {
+					config: parseTsconfig(tsconfigFullPath),
+					path: tsconfigFullPath,
+				};
+				tsconfigCache.set(tsconfigFullPath, tsconfig);
 			}
-		}
 
-		if (fileMatcher) {
-			transformOptions.tsconfigRaw = fileMatcher(
-				// Doesn't include query
-				this.resourcePath,
-			) as TransformOptions['tsconfigRaw'];
+			const filesMatcher = createFilesMatcher(tsconfig);
+			const matches = filesMatcher(resourcePath);
+
+			if (!matches) {
+				this.emitWarning(
+					new Error(`[esbuild-loader] The specified tsconfig at "${tsconfigFullPath}" was applied to the file "${resourcePath}" but does not match its "include" patterns`),
+				);
+			}
+
+			transformOptions.tsconfigRaw = tsconfig.config as TransformOptions['tsconfigRaw'];
+		} else {
+			/* Detect tsconfig file */
+
+			// Webpack shouldn't be loading the same path multiple times so doesn't need to be cached
+			const tsconfig = getTsconfig(resourcePath);
+			if (tsconfig) {
+				const fileMatcher = createFilesMatcher(tsconfig);
+				transformOptions.tsconfigRaw = fileMatcher(resourcePath) as TransformOptions['tsconfigRaw'];
+			}
 		}
 	}
 

tests/specs/tsconfig.ts

@@ -16,8 +16,20 @@ export default testSuite(({ describe }) => {
 			test('finds tsconfig.json and applies strict mode', async ({ onTestFinish }) => {
 				const fixture = await createFixture({
 					src: {
-						'index.ts': `module.exports = [${detectStrictMode}, require("./not-strict.ts")];`,
+						'index.ts': `module.exports = [
+							${detectStrictMode},
+							require("./not-strict.ts"),
+							require("./different-config/strict.ts"),
+						];`,
 						'not-strict.ts': `module.exports = ${detectStrictMode}`,
+						'different-config': {
+							'strict.ts': `module.exports = ${detectStrictMode}`,
+							'tsconfig.json': tsconfigJson({
+								compilerOptions: {
+									strict: true,
+								},
+							}),
+						},
 					},
 					'webpack.config.js': `
 					module.exports = {
@@ -66,7 +78,7 @@ export default testSuite(({ describe }) => {
 				const require = createRequire(import.meta.url);
 				expect(
 					require(path.join(fixture.path, 'dist/main.js')),
-				).toStrictEqual([true, false]);
+				).toStrictEqual([true, false, true]);
 			});
 
 			test('handles resource with query', async ({ onTestFinish }) => {
@@ -174,14 +186,90 @@ export default testSuite(({ describe }) => {
 
 				onTestFinish(async () => await fixture.rm());
 
-				await execa(webpackCli, {
+				const { stdout } = await execa(webpackCli, {
 					cwd: fixture.path,
 				});
 
+				expect(stdout).toMatch('does not match its "include" patterns');
+
 				const require = createRequire(import.meta.url);
 				expect(
 					require(path.join(fixture.path, 'dist/main.js')),
-				).toStrictEqual([false, true]);
+				).toStrictEqual([true, true]);
+			});
+
+			test('applies different tsconfig.json paths', async ({ onTestFinish }) => {
+				const fixture = await createFixture({
+					src: {
+						'index.ts': 'export class C { foo = 100; }',
+						'index2.ts': 'export class C { foo = 100; }',
+					},
+					'webpack.config.js': `
+					module.exports = {
+						mode: 'production',
+
+						optimization: {
+							minimize: false,
+						},
+
+						resolveLoader: {
+							alias: {
+								'esbuild-loader': ${JSON.stringify(esbuildLoader)},
+							},
+						},
+
+						module: {
+							rules: [
+								{
+									test: /index\\.ts$/,
+									loader: 'esbuild-loader',
+									options: {
+										tsconfig: './tsconfig.custom1.json',
+									}
+								},
+								{
+									test: /index2\\.ts$/,
+									loader: 'esbuild-loader',
+									options: {
+										tsconfig: './tsconfig.custom2.json',
+									}
+								}
+							],
+						},
+
+						entry: {
+							index1: './src/index.ts',
+							index2: './src/index2.ts',
+						},
+
+						output: {
+							libraryTarget: 'commonjs2',
+						},
+					};
+					`,
+					'tsconfig.custom1.json': tsconfigJson({
+						compilerOptions: {
+							useDefineForClassFields: false,
+						},
+					}),
+					'tsconfig.custom2.json': tsconfigJson({
+						compilerOptions: {
+							useDefineForClassFields: true,
+						},
+					}),
+				});
+
+				onTestFinish(async () => await fixture.rm());
+
+				await execa(webpackCli, {
+					cwd: fixture.path,
+				});
+
+				const code1 = await fixture.readFile('dist/index1.js', 'utf8');
+				expect(code1).toMatch('this.foo = 100;');
+
+				const code2 = await fixture.readFile('dist/index2.js', 'utf8');
+				expect(code2).toMatch('__publicField(this, "foo", 100);');
 			});
 		});