Question

JSLint does not like this code saying “‘b’ was used before it was defined”

var a = function () {
        b();
    },

    b = function () {
        alert("Hello, world!");
    };

a();   

but perfectly happy with this

var a, b;

a = function () {
    b();
};

b = function () {
    alert("Hello, world!");
};

a();   

But I am not defining anything in my second code snippet. I am merely declaring variable b.

So why is JSLint doing this? Is there a reason I should be declaring all my functions first?

PS I understand I could have just changed order of a and b, but in real project my functions are event handlers and sometimes they call each other, so it is probably not possible.

Answer 1

If your code is well-written and object-oriented, it is possible to declare your functions before they are used. But JSLint sets a lot of standards that really have little relevance to the functionality of your application, and I really doubt there are any performance implications declaring functions one way or the other.