Add _.propertyDeep and _.propertyDeepOf.

lodash.src.js

@@ -2598,6 +2598,31 @@
       };
     }
 
+    /**
+     * The base implementation of `_.propertyDeep` which does not coerce `keys` to strings.
+     *
+     * @private
+     * @param {string[]} keys Keys that specify the property to get.
+     * @returns {Function} Returns the new function.
+     */
+    function basePropertyDeep(keys) {
+      return function(object) {
+        if (object == null) {
+          return undefined;
+        }
+        var index = -1,
+            length = keys.length;
+
+        while (++index < length) {
+          object = object[keys[index]];
+          if (object == null) {
+            return undefined;
+          }
+        }
+        return object;
+      };
+    }
+
     /**
      * The base implementation of `_.pullAt` without support for individual
      * index arguments and capturing the removed elements.
@@ -11243,6 +11268,33 @@
       return baseProperty(key + '');
     }
 
+    /**
+     * This function is like `_.property` except it takes a `keys` array to get nested property.
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {string[]} keys Keys that specify the property to get.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { 'user': { 'name': 'fred' } },
+     *   { 'user': { 'name': 'barney', 'age': 36 } }
+     * ];
+     *
+     * var getName = _.propertyDeep(['user', 'name']);
+     * var getAge  = _.propertyDeep(['user', 'age']);
+     *
+     * _.map(users, getName);
+     * // => ['fred', 'barney']
+     *
+     * _.map(users, getAge);
+     * // => [undefined, 36]
+     */
+    function propertyDeep(keys) {
+      return basePropertyDeep(arrayMap(keys || [], baseToString));
+    }
+
     /**
      * The opposite of `_.property`; this method creates a function which returns
      * the property value of a given key on `object`.
@@ -11268,6 +11320,36 @@
       };
     }
 
+    /**
+     * The opposite of `_.propertyDeep`; this method creates a function which returns
+     * the property value of a given key path on `object`.
+     *
+     * @static
+     * @memberOf _
+     * @category Utility
+     * @param {Object} object The object to inspect.
+     * @returns {Function} Returns the new function.
+     * @example
+     *
+     * var users = [
+     *   { user: 'fredrick', nickname: 'fred' },
+     *   { user: 'bernard', nickname: 'barney' }
+     * ];
+     *
+     * var propertyOfUsers = _.propertyDeepOf(users);
+     *
+     * propertyOfUsers([0, 'nickname']);
+     * // => 'fred'
+     *
+     * propertyOfUsers([1, 'name']);
+     * // => 'bernard'
+     */
+    function propertyDeepOf(object) {
+      return function(keyPath) {
+        return resultDeep(object, keyPath);
+      };
+    }
+
     /**
      * Creates an array of numbers (positive and/or negative) progressing from
      * `start` up to, but not including, `end`. If `end` is not specified it is
@@ -11651,7 +11733,9 @@
     lodash.pick = pick;
     lodash.pluck = pluck;
     lodash.property = property;
+    lodash.propertyDeep = propertyDeep;
     lodash.propertyOf = propertyOf;
+    lodash.propertyDeepOf = propertyDeepOf;
     lodash.pull = pull;
     lodash.pullAt = pullAt;
     lodash.range = range;

test/test.js

@@ -11588,6 +11588,58 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.propertyDeep');
+
+  (function() {
+    test('should create a function that plucks a property value of a given object', 3, function() {
+      var object = { 'a': [1, 2], 'b': 3 },
+          prop = _.propertyDeep(['a', 1]);
+
+      strictEqual(prop.length, 1);
+      strictEqual(prop(object), 2);
+
+      prop = _.propertyDeep(['b']);
+      strictEqual(prop(object), 3);
+    });
+
+    test('should work with non-string `prop` arguments', 1, function() {
+      var prop = _.propertyDeep([1]);
+      strictEqual(prop([1, 2, 3]), 2);
+    });
+
+    test('should return a function even for falsey values', 1, function() {
+      var pass = true;
+
+      _.each(falsey, function(keys) {
+        pass = typeof _.propertyDeep(keys) == 'function'
+      });
+
+      ok(pass);
+    });
+
+    test('should pluck inherited property values', 1, function() {
+      function Foo() { this.a = 1; }
+      Foo.prototype.b = 2;
+
+      var prop = _.propertyDeep(['b']);
+      strictEqual(prop(new Foo), 2);
+    });
+
+    test('should work when `object` is nullish', 1, function() {
+      var values = [, null, undefined],
+          expected = _.map(values, _.constant(undefined));
+
+      var actual = _.map(values, function(value, index) {
+        var prop = _.propertyDeep(['a']);
+        return index ? prop(value) : prop();
+      });
+
+      deepEqual(actual, expected);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash.propertyOf');
 
   (function() {
@@ -11623,6 +11675,41 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.propertyDeepOf');
+
+  (function() {
+    test('should create a function that plucks a property value of a given key', 3, function() {
+      var object = { 'a': 1, 'b': 2 },
+          propOf = _.propertyDeepOf(object);
+
+      strictEqual(propOf.length, 1);
+      strictEqual(propOf(['a']), 1);
+      strictEqual(propOf(['b']), 2);
+    });
+
+    test('should pluck inherited property values', 1, function() {
+      function Foo() { this.a = 1; }
+      Foo.prototype.b = 2;
+
+      var propOf = _.propertyDeepOf(new Foo);
+      strictEqual(propOf(['b']), 2);
+    });
+
+    test('should work when `object` is nullish', 1, function() {
+      var values = [, null, undefined],
+          expected = _.map(values, _.constant(undefined));
+
+      var actual = _.map(values, function(value, index) {
+        var propOf = index ? _.propertyDeepOf(value) : _.propertyDeepOf();
+        return propOf(['a']);
+      });
+
+      deepEqual(actual, expected);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash.pull');
 
   (function() {
@@ -16581,7 +16668,7 @@
 
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
-    test('should accept falsey arguments', 214, function() {
+    test('should accept falsey arguments', 216, function() {
       var emptyArrays = _.map(falsey, _.constant([])),
           isExposed = '_' in root,
           oldDash = root._;