--- /dev/null
+var baseCallback = require('./baseCallback'),
+ binaryIndex = require('./binaryIndex'),
+ binaryIndexBy = require('./binaryIndexBy');
+
+/**
+ * Creates a `_.sortedIndex` or `_.sortedLastIndex` function.
+ *
+ * @private
+ * @param {boolean} [retHighest] Specify returning the highest qualified index.
+ * @returns {Function} Returns the new index function.
+ */
+function createSortedIndex(retHighest) {
+ return function(array, value, iteratee, thisArg) {
+ return iteratee == null
+ ? binaryIndex(array, value, retHighest)
+ : binaryIndexBy(array, value, baseCallback(iteratee, thisArg, 1), retHighest);
+ };
+}
+
+module.exports = createSortedIndex;