diff --git a/Userland/Libraries/LibJS/AST.cpp b/Userland/Libraries/LibJS/AST.cpp index 9945689bb1..1fb878c2be 100644 --- a/Userland/Libraries/LibJS/AST.cpp +++ b/Userland/Libraries/LibJS/AST.cpp @@ -239,16 +239,16 @@ Value CallExpression::execute(Interpreter& interpreter, GlobalObject& global_obj VERIFY(!callee.is_empty()); - if (!callee.is_function()) { - throw_type_error_for_callee(interpreter, global_object, callee, "function"sv); - return {}; - } - MarkedValueList arg_list(vm.heap()); argument_list_evaluation(interpreter, global_object, m_arguments, arg_list); if (interpreter.exception()) return {}; + if (!callee.is_function()) { + throw_type_error_for_callee(interpreter, global_object, callee, "function"sv); + return {}; + } + auto& function = callee.as_function(); if (is(*m_callee) && static_cast(*m_callee).string() == vm.names.eval.as_string() && &function == global_object.eval_function()) { diff --git a/Userland/Libraries/LibJS/Tests/functions/function-evaluation-order.js b/Userland/Libraries/LibJS/Tests/functions/function-evaluation-order.js new file mode 100644 index 0000000000..15584202db --- /dev/null +++ b/Userland/Libraries/LibJS/Tests/functions/function-evaluation-order.js @@ -0,0 +1,30 @@ +test("callee is evaluated before arguments", () => { + function foo() {} + const values = []; + + [foo][(values.push("callee"), 0)](values.push("args")); + + expect(values).toEqual(["callee", "args"]); +}); + +test("arguments are evaluated in order", () => { + function foo() {} + const values = []; + + foo(values.push("arg1"), values.push("arg2"), values.push("arg3")); + + expect(values).toEqual(["arg1", "arg2", "arg3"]); +}); + +test("arguments are evaluated before callee is checked for its type", () => { + const values = []; + + expect(() => { + "foo"(values.push("args")); + }).toThrowWithMessage(TypeError, "foo is not a function"); + expect(values).toEqual(["args"]); + + expect(() => { + "foo"(bar); + }).toThrowWithMessage(ReferenceError, "'bar' is not defined"); +});