gistfile1.txt

function each(objOrArr, callback) {
    /* Test to see if the argument is an array first since `typeof` does not
    distinguish between arrays and plain objects. */
    if (Array.isArray(objOrArr)) {
    
        /* The `forEach` method of arrays does exactly what we want. The
        function you pass to it is called for each item in the array and is
        passed the item and its index. */
        objOrArr.forEach(callback);
    } else {
        /* If the argument is not an array, assume that it is an object and
        loop through all of its properties. */

        for (var key in objOrArr) {
            /* The `key` variable is now set to the name of the current
            property in the loop. We can now use `key` to access the value
            of the current property in the loop and pass that value, along
            with the key, to the callback function. */

            callback(objOrArr[key], key); 
        }
    }
}