Find out if a Closure Provides a Method (JavaScript Module Pattern)

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!

No, there is not. You cannot inspect the return value without having it. — Felix Kling
– Felix Kling, Commented Aug 15, 2011 at 12:00
@JonnyReeves, you might find this link useful stackoverflow.com/questions/4849369/… — reevesy
– reevesy, Commented Aug 17, 2011 at 17:42

JonnyReeves · Accepted Answer · 2012-08-16 15:15:45Z

1

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

answered Aug 16, 2012 at 15:15

JonnyReeves

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