Javascript function expression typeof undefined

Question

Below is from MDN "Function Expression". Shouldn't typeof baz be function, not undefined? Why is bar === baz false?

var foo = function() {}
foo.name // "foo"

var foo2 = foo
foo2.name // "foo"

var bar = function baz() {}
bar.name // "baz"

console.log(foo === foo2); // true
console.log(typeof baz); // undefined
console.log(bar === baz); // false (errors because baz == undefined)

`baz` is the name of the function (Google "Named function") but on the function itself. — Dominik, Nov 17 '20 at 21:25
The scope of the name in a named function expression is just the function body. — Barmar, Nov 17 '20 at 21:26

score 0 · Answer 1 · answered Nov 17 '20 at 21:41

You’re mixing function declaration styles.

If there’s a var, the line will get interpreted at runtime. If it’s function name() it will get interpreted at compile time.

If you mix it, you’ll get the function expression (hoisting) instead of the function declaration. And so you get bar instead of baz

Javascript function expression typeof undefined

1 Answers1