how to detect a function was called with javascript

Question

I have a javascript function.

How to check:

• if function was called ( in section have this function), then not

Answer 1

Use decorator pattern.

// your function definition
function yourFunction() {}

// decorator
function callItOnce(fn) {
    var called = false;
    return function() {
        if (!called) {
            called = true;
            return fn();
        }
        return;
    }
}

yourFunction(); // it runs
yourFunction(); // it runs    
yourFunction = callItOnce(yourFunction);
yourFunction(); // it runs
yourFunction(); // null

This solution provides a side-effect free way for achieving your goal. You don't have to modify your original function. It works nice even with library functions. You may assign a new name to the decorated function to preserve the original function.

var myLibraryFunction = callItOnce(libraryFunction);
myLibraryFunction(); // it runs
myLibraryFunction(); // null
libraryFunction(); // it runs