fix: Preserve Unicode escape sequences in transformation

src/__tests__/transform.test.ts

@@ -9,12 +9,12 @@ describe(transform, () => {
     const testHooks: Hook[] = [new TestHook(/foo/), new TestHook(/bar/)];
     const transforms = testHooks.map((t) => jest.spyOn(t, "transform"));
 
-    expect(transform("'hello'", new URL("file:///foo"), testHooks)).toBe('"hello";\n"/foo/";\n');
+    expect(transform("'hello'", new URL("file:///foo"), testHooks)).toBe("'hello';\n\"/foo/\";\n");
     expect(transforms[0]).toBeCalled();
     expect(transforms[1]).not.toBeCalled();
     transforms[0].mockReset();
 
-    expect(transform("'hello'", new URL("file:///bar"), testHooks)).toBe('"hello";\n"/bar/";\n');
+    expect(transform("'hello'", new URL("file:///bar"), testHooks)).toBe("'hello';\n\"/bar/\";\n");
     expect(transforms[0]).not.toBeCalled();
     expect(transforms[1]).toBeCalled();
     transforms[1].mockReset();
@@ -40,8 +40,23 @@ describe(transform, () => {
 
     expect(jest.mocked(warn).mock.calls).toMatchSnapshot();
   });
+
+  it("transforms unicode correctly", () => {
+    const input = `const a = "\\u{1D306}";\n`;
+    // Ensure that "\u{1D306}" is not converted to "t̆".
+    expect(transform(input, new URL("file:///foo"), [new IdentityHook()])).toBe(input);
+  });
 });
 
+class IdentityHook implements Hook {
+  shouldInstrument(): boolean {
+    return true;
+  }
+  transform(program: ESTree.Program): ESTree.Program {
+    return program;
+  }
+}
+
 class TestHook implements Hook {
   constructor(public pattern: RegExp) {}
 

src/transform.ts

@@ -84,6 +84,7 @@ export default function transform(code: string, url: URL, hooks = defaultHooks):
       loc: true,
       module: true,
       onComment: comments,
+      raw: true,
     });
 
     const xformed = hook.transform(tree, getSourceMap_(), comments);