function shouldThrow(func, errorMessage) { var errorThrown = false; var error = null; try { func(); } catch (e) { errorThrown = true; error = e; } if (!errorThrown) throw new Error('not thrown'); if (String(error) !== errorMessage) throw new Error(`bad error: ${String(error)}`); } noInline(shouldThrow); function shouldBe(actual, expected) { if (actual !== expected) throw new Error(`bad value: ${String(actual)}`); } noInline(shouldBe); bar = 0; function foo(code) { eval(code); return (function () { return bar; }()); } shouldBe(foo(`42`), 0); $.evalScript(`const bar = 42`); shouldBe(foo(`42`), 42); shouldBe(foo(`var bar = 1`), 1); shouldBe(foo(`42`), 42);