Javascript 函数返回一个对象，但答案未定义

Question

I'm doing this quiz question http://davidshariff.com/js-quiz/#q=2 The question is:

 function aaa() { return { test: 1 } } console.log(typeof aaa())

The prompted answer for console.log is undefined but I thought it should be an 'object'

Can anyone explain why?

Answer 1

You haven't copied the code correctly, indentation is important here. The original code is

function aaa() {
    return
    {
        test: 1
    };
}
alert(typeof aaa());

As you can see there's a new line after return , which after automatic semicolon insertion (ASI), looks as follows:

function aaa() {
    return;
    {
        test: 1
    };
}
alert(typeof aaa());

So the return result of this function will be undefined , since there's no return value and the code is unreachable after the return statement.