Question

Given the following code, is there any way for me to detect if the closure returned by calling fn() contains a given method without having to execute fn itself?

// Example function which provides a closure with an 'execute' method.
var fn = function () {
    return {
        execute: function () {
        }
    }; 
};


// Test for the presense of an 'execute' method in the function's closure
if ("function" === typeof fn().execute) {
    print("supplied function includes an execute method");
} else {
    print("supplied function does not include an execute method");
}

Thanks!

Answer 1

No, there is not. You cannot inspect the return value without having it. – Felix Kling