javascript - shortcut for calling a function at the same time it is defined

Question

hi,

to call a function at the same time it's defined, i had been using:

var newfunc = function() {
    alert('hi');
};
newfunc();

is the following the correct way of combining these 2:

var newfunc = function() {
    alert('hi');
}();

Answer 1

No. Your second example will immediately call the anonymous function and assign its return value to newfunc.

adamse describes an approach which appears to work. I'd still avoid the approach as the two step process is easier to read and thus will be easier to maintain.

Answer 2

var newfunc = function f() {
    alert("hi!");
    return f;
}();

Having a named function expressions allows the function to recursively call itself or, in this case, return itself. This function will always return itself, however, which might be an annoyance.

Answer 3

If I understand your question correctly, give this a try:

(f = function (msg) {
  msg =  msg ? msg : 'default value';
  alert(msg); }
)();


f('I\'m not the default value!');

You'll get two alerts, the first one will say "default value" and the second will say "I'm not the default value. You can see it in action at jsBin. Click 'preview' to make it run.