--- /dev/null
+var baseMerge = require('./_baseMerge'),
+ isObject = require('./isObject');
+
+/**
+ * Used by `_.defaultsDeep` to customize its `_.merge` use to merge source
+ * objects into destination objects that are passed thru.
+ *
+ * @private
+ * @param {*} objValue The destination value.
+ * @param {*} srcValue The source value.
+ * @param {string} key The key of the property to merge.
+ * @param {Object} object The parent object of `objValue`.
+ * @param {Object} source The parent object of `srcValue`.
+ * @param {Object} [stack] Tracks traversed source values and their merged
+ * counterparts.
+ * @returns {*} Returns the value to assign.
+ */
+function customDefaultsMerge(objValue, srcValue, key, object, source, stack) {
+ if (isObject(objValue) && isObject(srcValue)) {
+ // Recursively merge objects and arrays (susceptible to call stack limits).
+ stack.set(srcValue, objValue);
+ baseMerge(objValue, srcValue, undefined, customDefaultsMerge, stack);
+ stack['delete'](srcValue);
+ }
+ return objValue;
+}
+
+module.exports = customDefaultsMerge;