fix: preserve import.meta.url despite target

fixes #115

Author: privatenumber

src/rollup/plugins/esbuild.ts

@@ -19,6 +19,17 @@ export const esbuildTransform = (
 			const result = await transform(code, {
 				...options,
 
+				supported: {
+					/**
+					 * esbuild is used for TS, syntax lowering, & define, but
+					 * we'll ignore import.meta as it injects a polyfill that
+					 * may break if the output is ESM
+					 *
+					 * https://esbuild.github.io/try/#dAAwLjI1LjAAe3RhcmdldDogWydlczIwMTcnXX0AY29uc29sZS5sb2coaW1wb3J0Lm1ldGEudXJsKQ
+					 */
+					'import-meta': true,
+				},
+
 				loader: 'default',
 
 				// https://github.com/evanw/esbuild/issues/1932#issuecomment-1013380565

tests/specs/builds/output-module.ts

@@ -364,5 +364,24 @@ export default testSuite(({ describe }, nodePath: string) => {
 			const content = await fixture.readFile('dist/dynamic-imports.mjs', 'utf8');
 			expect(content).toMatch('import(');
 		});
+
+		// https://github.com/privatenumber/pkgroll/issues/115
+		test('import.meta.url should be preserved', async () => {
+			await using fixture = await createFixture({
+				'src/index.js': 'console.log(import.meta.url)',
+				'package.json': createPackageJson({
+					exports: './dist/index.mjs',
+				}),
+			});
+
+			const pkgrollProcess = await pkgroll(['--target=es2017'], {
+				cwd: fixture.path,
+				nodePath,
+			});
+			expect(pkgrollProcess.exitCode).toBe(0);
+
+			const content = await fixture.readFile('dist/index.mjs', 'utf8');
+			expect(content).toMatch('import.meta.url');
+		});
 	});
 });