Bump to v4.0.0.

internal/copyObjectWith.js

@@ -0,0 +1,30 @@
+define(['./assignValue'], function(assignValue) {
+
+  /**
+   * This function is like `copyObject` except that it accepts a function to
+   * customize copied values.
+   *
+   * @private
+   * @param {Object} source The object to copy properties from.
+   * @param {Array} props The property names to copy.
+   * @param {Object} [object={}] The object to copy properties to.
+   * @param {Function} [customizer] The function to customize copied values.
+   * @returns {Object} Returns `object`.
+   */
+  function copyObjectWith(source, props, object, customizer) {
+    object || (object = {});
+
+    var index = -1,
+        length = props.length;
+
+    while (++index < length) {
+      var key = props[index],
+          newValue = customizer ? customizer(object[key], source[key], key, object, source) : source[key];
+
+      assignValue(object, key, newValue);
+    }
+    return object;
+  }
+
+  return copyObjectWith;
+});