test: add esm loader test (#5383)

* test: add esm loader test

* test: add esm loader test

---------

Co-authored-by: Josh Goldberg ✨ <[email protected]>

Author: legendecas

eslint.config.js

@@ -68,6 +68,16 @@ module.exports = [
       sourceType: 'module'
     }
   },
+  {
+    files: [
+      'test/compiler-esm/*.js'
+    ],
+    languageOptions: {
+      sourceType: 'module',
+      // For top-level await support.
+      ecmaVersion: 2022,
+    }
+  },
   {
     files: ['test/**/*.{js,mjs}'],
     languageOptions: {

test/compiler-esm/package.json

@@ -0,0 +1,4 @@
+{
+  "//": "Setting default type for .ts files as ESM as well",
+  "type": "module"
+}

test/compiler-esm/test-tla.js

@@ -0,0 +1,11 @@
+const obj = { foo: 'bar' };
+
+describe('esm written in esm with top-level-await', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: 'bar' });
+  });
+});
+
+await undefined;
+
+export const foo = 'bar';

test/compiler-esm/test-tla.js.compiled

@@ -0,0 +1,11 @@
+const obj = { foo: 'bar' };
+
+describe('esm written in esm with top-level-await', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: 'bar' });
+  });
+});
+
+await undefined;
+
+export const foo = 'bar';

test/compiler-esm/test-tla.ts

@@ -0,0 +1,14 @@
+const obj: unknown = { foo: 'bar' };
+enum Foo {
+  Bar = 'bar',
+}
+
+describe('esm written in esm with top-level-await', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: Foo.Bar });
+  });
+});
+
+await undefined;
+
+export const foo = 'bar';

test/compiler-esm/test-tla.ts.compiled

@@ -0,0 +1,14 @@
+const obj = { foo: 'bar' };
+const Foo = {
+  Bar: 'bar',
+};
+
+describe('esm written in esm with top-level-await', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: Foo.Bar });
+  });
+});
+
+await undefined;
+
+export const foo = 'bar';

test/compiler-esm/test.js

@@ -0,0 +1,9 @@
+const obj = { foo: 'bar' };
+
+describe('esm written in esm', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: 'bar' });
+  });
+});
+
+export const foo = 'bar';

test/compiler-esm/test.js.compiled

@@ -0,0 +1,9 @@
+const obj = { foo: 'bar' };
+
+describe('esm written in esm', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: 'bar' });
+  });
+});
+
+export const foo = 'bar';

test/compiler-esm/test.ts

@@ -0,0 +1,12 @@
+const obj: unknown = { foo: 'bar' };
+enum Foo {
+  Bar = 'bar',
+};
+
+describe('esm written in esm', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: Foo.Bar });
+  });
+});
+
+export const foo = 'bar';

test/compiler-esm/test.ts.compiled

@@ -0,0 +1,12 @@
+const obj = { foo: 'bar' };
+const Foo = {
+  Bar: 'bar',
+};
+
+describe('esm written in esm', () => {
+  it('should work', () => {
+    expect(obj, 'to equal', { foo: Foo.Bar });
+  });
+});
+
+export const foo = 'bar';