Add _.add/_.sum methods

lodash.src.js

@@ -11159,6 +11159,44 @@
 
     /*------------------------------------------------------------------------*/
 
+    /**
+     * Adds two numbers.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} augend The first number to add.
+     * @param {number} addend The second number to add.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.add(6, 4);
+     * // => 10
+     */
+    function add(augend, addend) {
+      return augend + addend;
+    }
+
+    /**
+     * Calculates the sum of an array of numbers.
+     *
+     * @static
+     * @memberOf _
+     * @category Math
+     * @param {number} array The numbers to add.
+     * @returns {number} Returns the sum.
+     * @example
+     *
+     * _.sum([4, 6, 2]);
+     * // => 12
+     */
+    function sum(array) {
+      if (!isArray(array) || array.length === 0) return NaN;
+      return arrayReduce(array, add, 0);
+    }
+
+    /*------------------------------------------------------------------------*/
+
     // Ensure wrappers are instances of `baseLodash`.
     lodash.prototype = baseLodash.prototype;
 
@@ -11301,6 +11339,7 @@
     /*------------------------------------------------------------------------*/
 
     // Add functions that return unwrapped values when chaining.
+    lodash.add = add;
     lodash.attempt = attempt;
     lodash.camelCase = camelCase;
     lodash.capitalize = capitalize;
@@ -11370,6 +11409,7 @@
     lodash.sortedLastIndex = sortedLastIndex;
     lodash.startCase = startCase;
     lodash.startsWith = startsWith;
+    lodash.sum = sum;
     lodash.template = template;
     lodash.trim = trim;
     lodash.trimLeft = trimLeft;

test/test.js

@@ -15098,6 +15098,28 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('lodash.add');
+
+  (function() {
+    test('should add two numbers together', 1, function() {
+      var actual = _.add(6, 4);
+      equal(actual, 10);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
+  QUnit.module('lodash.sum');
+
+  (function() {
+    test('should return the sum of an array of numbers', 1, function() {
+      var actual = _.sum([6, 4, 2]);
+      equal(actual, 12);
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash(...).commit');
 
   (function() {
@@ -15579,6 +15601,7 @@
 
   (function() {
     var funcs = [
+      'add',
       'clone',
       'contains',
       'every',
@@ -15610,6 +15633,7 @@
       'parseInt',
       'pop',
       'shift',
+      'sum',
       'random',
       'reduce',
       'reduceRight',
@@ -15756,6 +15780,33 @@
 
   /*--------------------------------------------------------------------------*/
 
+  QUnit.module('"Math" category methods');
+
+  (function() {
+    var mathArrayMethods = [
+      'sum'
+    ];
+
+    _.each(mathArrayMethods, function(methodName) {
+      var func = _[methodName];
+
+      test('`_.' + methodName + '` should return NaN when passing a value other than an array', 5, function() {
+        var values = [undefined, null, 0, 'foo', {}];
+        _.each(values, function(value) {
+          var actual = _[methodName](value);
+          deepEqual(actual, NaN);
+        });
+      });
+
+      test('`_.' + methodName + '` should return NaN when passing an empty array', 1, function() {
+        var actual = _[methodName]([]);
+        deepEqual(actual, NaN);
+      });
+    });
+  }());
+
+  /*--------------------------------------------------------------------------*/
+
   QUnit.module('lodash methods');
 
   (function() {
@@ -15832,7 +15883,7 @@
 
     var acceptFalsey = _.difference(allMethods, rejectFalsey);
 
-    test('should accept falsey arguments', 209, function() {
+    test('should accept falsey arguments', 211, function() {
       var emptyArrays = _.map(falsey, _.constant([])),
           isExposed = '_' in root,
           oldDash = root._;