Add _.resultDeep.

lodash.src.js

@@ -9796,6 +9796,45 @@
       return isFunction(value) ? value.call(object) : value;
     }
 
+    /**
+     * Resolves the value of `keyPath` on `object`. If any values along `keyPath`
+     * is a function it is invoked with the `this` binding of `object` and its
+     * result is used to resolve the remainder of the `keyPath` rather than the
+     * function itself. If at any point along the `keyPath` the value is
+     * `undefined` the `defaultValue` is returned.
+     *
+     * @static
+     * @memberOf _
+     * @category Object
+     * @param {Object} object The object to query.
+     * @param {array} keyPath The key path of the properties to resolve.
+     * @param {*} [defaultValue] The value returned if the property value
+     *  resolves to `undefined`.
+     * @returns {*} Returns the resolved value.
+     * @example
+     *
+     * var object = {
+     *  'user': 'fred',
+     *  'dates': { 'birthdate': '03/17/1988', anniversary: '07/29/2012' }
+     * };
+     *
+     * _.resultDeep(object, ['user']);
+     * // => 'fred'
+     *
+     * _.resultDeep(object, ['user', 'dates', 'anniversary']);
+     * // => '07/29/2012'
+     *
+     * _.resultDeep(object, ['status', 'timestamp'], _.constant('busy'));
+     * // => 'busy'
+     */
+    function resultDeep(object, keyPath, defaultValue) {
+      arrayEach(dropRight(keyPath), function(key) {
+        object = result(object, key);
+        return object != null;
+      });
+      return result(object, last(keyPath), defaultValue);
+    }
+
     /**
      * An alternative to `_.reduce`; this method transforms `object` to a new
      * `accumulator` object which is the result of running each of its own enumerable
@@ -11732,6 +11771,7 @@
     lodash.reduceRight = reduceRight;
     lodash.repeat = repeat;
     lodash.result = result;
+    lodash.resultDeep = resultDeep;
     lodash.runInContext = runInContext;
     lodash.size = size;
     lodash.snakeCase = snakeCase;

test/test.js

@@ -12501,6 +12501,52 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.resultDeep');
+
+  (function() {
+    var object = {
+      'a': { d: 1 },
+      'b': null,
+      'c': function() { return this.a; }
+    };
+
+    test('should resolve property values', 4, function() {
+      strictEqual(_.resultDeep(object, ['a', 'd']), 1);
+      strictEqual(_.resultDeep(object, ['b']), null);
+      strictEqual(_.resultDeep(object, ['c', 'd']), 1);
+      strictEqual(_.resultDeep(object, ['d']), undefined);
+    });
+
+    test('should return `undefined` when `object` is nullish', 2, function() {
+      strictEqual(_.resultDeep(null, ['a']), undefined);
+      strictEqual(_.resultDeep(undefined, ['a']), undefined);
+    });
+
+    test('should return the specified default value for undefined properties', 1, function() {
+      var values = empties.concat(true, new Date, 1, /x/, 'a');
+
+      var expected = _.transform(values, function(result, value) {
+        result.push(value, value);
+      });
+
+      var actual = _.transform(values, function(result, value) {
+        result.push(
+          _.resultDeep(object, ['d'], value),
+          _.resultDeep(null, ['d'], value)
+        );
+      });
+
+      deepEqual(actual, expected);
+    });
+
+    test('should execute default function values', 1, function() {
+      var actual = _.resultDeep(object, ['d'], object.c);
+      strictEqual(actual, object.a);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash.rest');
 
   (function() {
@@ -16535,7 +16581,7 @@
 
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
-    test('should accept falsey arguments', 213, function() {
+    test('should accept falsey arguments', 214, function() {
       var emptyArrays = _.map(falsey, _.constant([])),
           isExposed = '_' in root,
           oldDash = root._;