Bump to v4.1.0.

_baseSum.js

@@ -0,0 +1,29 @@
+define([], function() {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * The base implementation of `_.sum` without support for iteratee shorthands.
+   *
+   * @private
+   * @param {Array} array The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @returns {number} Returns the sum.
+   */
+  function baseSum(array, iteratee) {
+    var result,
+        index = -1,
+        length = array.length;
+
+    while (++index < length) {
+      var current = iteratee(array[index]);
+      if (current !== undefined) {
+        result = result === undefined ? current : (result + current);
+      }
+    }
+    return length ? result : 0;
+  }
+
+  return baseSum;
+});