Also, named function expressions are necessary for recursion since arguments.callee is being removed.

@zachleat
I think you’re missing the difference between declaration and expression. What @jdalton said should pretty much answer your question.

@eyelidlessness
I don’t see how two function declarations with same-named identifier is a syntax error in ES3. Could you point me to a particular section in the specs describing this?

JavaScript is ought to have a variable binding construct, “let” or something. Then you wouldn’t need so much monkeying.

Actually, “var I = function(x){return x}” and “function I(x){return x}” have a subtle difference. The latter permits mutually recursive definitions, while the former is pretty limited in this respect.

Now, if we give people that “let” form (and also a “let*” in Scheme parlance), we don’t need to “mistify” ourselves with nonsense like the “named function expressions”.

function g() { return 1; }
if(false) {
function g() { return 2; }
}

is technically a syntax error. Function declarations are evaluated prior to script execution, and multiple declarations of the same function in the same scope is invalid. Some engines favor the second declaration simply because handling of the error is not defined.

It seems to obey function level scoping. If I have:

function g() { return 1; }
if(false) {
function g() { return 2; }
}

Of course, you’d expect g() to return 2, JS doesn’t have a different scope for if statements. It’s identical to:

var g;
g = function() { return 1; }
g = function() { return 2; }

What am I missing?