feat(codemode): support void and Object.is (#37332)

packages/codemode/test/parity.test.ts

@@ -99,6 +99,19 @@ describe("H4: typeof on an undeclared identifier is 'undefined'", () => {
   })
 })
 
+describe("unary void", () => {
+  test("evaluates its operand and returns undefined", async () => {
+    expect(await value(`let count = 0; const result = void (count += 1); return [count, result === undefined]`)).toEqual([
+      1,
+      true,
+    ])
+  })
+
+  test("discards opaque values", async () => {
+    expect(await value(`return void tools === undefined`)).toBe(true)
+  })
+})
+
 describe("H1: NaN/Infinity flow as intermediates and normalize to null at the boundary", () => {
   test("guards run instead of the program crashing on a transient NaN", async () => {
     expect(await value(`return parseInt("abc") || 0`)).toBe(0)

packages/codemode/test/stdlib.test.ts

@@ -593,6 +593,24 @@ describe("Set", () => {
 })
 
 describe("stdlib integration", () => {
+  test("Object.is uses SameValue semantics", async () => {
+    expect(
+      await value(`
+        const object = {}
+        return [
+          Object.is(NaN, NaN),
+          Object.is(0, -0),
+          Object.is(object, object),
+          Object.is({}, {}),
+        ]
+      `),
+    ).toEqual([true, false, true, false])
+  })
+
+  test("Object.is rejects opaque runtime references", async () => {
+    expect((await error(`return Object.is(Math.max, Math.max)`)).kind).toBe("InvalidDataValue")
+  })
+
   test("Object values and entries accept arrays", async () => {
     expect(await value(`return [Object.values(["a", "b"]), Object.entries(["a", "b"])]`)).toEqual([
       ["a", "b"],