How to **correctly** debounce an event that will be triggered many times with identical arguments.

debouncer.js

function debounce(fn, debounceDuration){
    // summary:
    //      Returns a debounced function that will make sure the given 
    //      function is not triggered too much.
    // fn: Function
    //      Function to debounce.
    // debounceDuration: Number
    //      OPTIONAL. The amount of time in milliseconds for which we 
    //      will debounce the function. (defaults to 100ms)

    debounceDuration = debounceDuration || 100;

    return function(){
        if(!fn.debouncing){
            var args = Array.prototype.slice.apply(arguments);
            fn.lastReturnVal = fn.apply(window, args);
            fn.debouncing = true;
        }
        clearTimeout(fn.debounceTimeout);
        fn.debounceTimeout = setTimeout(function(){
            fn.debouncing = false;
        }, debounceDuration);
        
        return fn.lastReturnVal;
    };
};

The function only triggers once and caches the result for N milliseconds. That might not be the expected behavior for a debounce function.

[…] a function, that, as long as it continues to be invoked, will not be triggered. The function will be called after it stops being called for N milliseconds. (https://davidwalsh.name/javascript-debounce-function)