Convert string in Object or Array style notation to a reference

A Javascript function to convert a string in dotted and/or array notation into a reference. e.g. "shallow[2].two[1][3].deepest"

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JavaScript

// By Scott Donnelly, MIT Licensed.
// Based on the answer to the StackOverflow question
// "Convert string in dot notation to reference" by ninjagecko
// http://stackoverflow.com/a/6394168/642703
// added empty string handling and array notation handling.

// I use this with AngularJS, to resolve references passed to
// a directive via an HTML attribute.

// This does not handle nested references - there is no way to resolve the nested
// variable references without using eval(),
// as described here http://stackoverflow.com/questions/598878

string_to_ref = function (object, reference) {
    function arr_deref(o, ref, i) {
        return !ref ? o : (o[ref.slice(0, i ? -1 : ref.length)]);
    }
    function dot_deref(o, ref) {
    	console.log(ref);
        return !ref ? o : ref.split('[').reduce(arr_deref, o);
    }
    return reference.split('.').reduce(dot_deref, object);
};

// Test object style references
test("function string_to_ref", 8, function() {    
    var obj_1 = ["zero", [ "deep-zero", "deep-one", "deep-two" ], {two: "two"}, "three" ];
    var obj_2 = {
        inner: { deeper: { deepest: "got it!" } },
        shallow: [
            { zero: "shallow zero"},
            { one: "shallow one" },
            {
                two: [
                    "deep zero", [
                        "deeper zero",
                        "deeper one",
                        "deeper two", {
                            deep: {deepest : "It Works!" }
                        }
                  	]
               	]
        	}
        ]
	};
    
    strictEqual(string_to_ref(obj_2, ""), obj_2, "Empty string");
    strictEqual(string_to_ref(obj_2, "shallow"), obj_2.shallow, "Single string");
    strictEqual(string_to_ref(obj_2, "inner.deeper.deepest"), obj_2.inner.deeper.deepest, "Multiple dotted");
    strictEqual(string_to_ref(obj_1, "[1]"), obj_1[1], "Single array");
    strictEqual(string_to_ref(obj_1, "[1][2]"), obj_1[1][2], "Multiple array");
   ...