javascript：传递函数名称与IIFE

Question

(Hoping I've got the terminology right...)

My code, much simplified:

function foo(parm1, fn){
    // do stuff with parm1, and then...
    window[fn]();
}

function bar(){
    // do the other thing
}

Which is then invoked as:

foo('some string', 'bar');

I'd like to use a function expression(?), like so:

foo('some string', function(){ // do the other thing });

while retaining the option to pass a function name as in the first example for when what 'bar' has to do is many steps. I've tried

function foo(parm1, fn){
    // do stuff with parm1, and then...
    if(typeof fn != 'function'){
        window[fn]();
    } else {
        return true;
    }
}

foo('some string', function(){ // but this never fires });

Can I have it both ways?

Answer 1

You can. You forgot to call fn if it is a function:

if(typeof fn != 'function'){
    window[fn]();
} else {
    fn(); // fn is (probably) a function so lets call it
}