Add _.update.

lodash.js

@@ -3449,6 +3449,19 @@
       return object;
     }
 
+    /**
+     * The base implementation of `_.update`.
+     *
+     * @private
+     * @param {Object} object The object to query.
+     * @param {Array|string} path The path of the property to update.
+     * @param {Function} updater The function to produce the updated value.
+     * @returns {Object} Returns `object`.
+     */
+    function baseUpdate(object, path, updater) {
+      return baseSet(object, path, updater(baseGet(object, path)));
+    }
+
     /**
      * The base implementation of `setData` without support for hot loop detection.
      *
@@ -11900,6 +11913,37 @@
       return object == null ? object : baseSet(object, path, value);
     }
 
+    /**
+     * Updates the value at `path` of `object` with given `func`. If a portion
+     * of `path` doesn't exist it's created. Arrays are created for missing index
+     * properties while objects are created for all other missing properties.
+     * The `func` is invoked with `value` at `path` of `object`: (value).
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to modify.
+     * @param {Array|string} path The path of the property to set.
+     * @param {Function} updater The function to produce the updated value.
+     * @returns {Object} Returns the updated `object`.
+     * @example
+     *
+     * var object = { 'a': [{ 'b': { 'c': 3, 'd': '11' } }] };
+     *
+     * _.update(object, 'a[0].b.c', function(n) { return n + 10; });
+     * console.log(object.a[0].b.c);
+     * // => 13
+     *
+     * _.update(object, 'x[0].y.z', function(n) { return n ? n + 1 : 0; });
+     * console.log(object.x[0].y.z);
+     * // => 0
+     */
+    function update(object, path, updater) {
+      return object == null
+        ? object
+        : baseUpdate(object, path, baseCastFunction(updater));
+    }
+
     /**
      * This method is like `_.set` except that it accepts `customizer` which is
      * invoked to produce the objects of `path`.  If `customizer` returns `undefined`
@@ -14555,6 +14599,7 @@
     lodash.unset = unset;
     lodash.unzip = unzip;
     lodash.unzipWith = unzipWith;
+    lodash.update = update;
     lodash.values = values;
     lodash.valuesIn = valuesIn;
     lodash.without = without;