added unit testing, and started implementing unit tests...phew

node_modules/lodash/sortedIndexOf.js

@@ -0,0 +1,31 @@
+var baseSortedIndex = require('./_baseSortedIndex'),
+    eq = require('./eq');
+
+/**
+ * This method is like `_.indexOf` except that it performs a binary
+ * search on a sorted `array`.
+ *
+ * @static
+ * @memberOf _
+ * @since 4.0.0
+ * @category Array
+ * @param {Array} array The array to inspect.
+ * @param {*} value The value to search for.
+ * @returns {number} Returns the index of the matched value, else `-1`.
+ * @example
+ *
+ * _.sortedIndexOf([4, 5, 5, 5, 6], 5);
+ * // => 1
+ */
+function sortedIndexOf(array, value) {
+  var length = array == null ? 0 : array.length;
+  if (length) {
+    var index = baseSortedIndex(array, value);
+    if (index < length && eq(array[index], value)) {
+      return index;
+    }
+  }
+  return -1;
+}
+
+module.exports = sortedIndexOf;