Add support for converting maps to _.toPairs and _.toPairsIn.

lodash.js

@@ -2674,9 +2674,7 @@
      */
     function baseGetAllKeys(object, keysFunc, symbolsFunc) {
       var result = keysFunc(object);
-      return isArray(object)
-        ? result
-        : arrayPush(result, symbolsFunc(object));
+      return isArray(object) ? result : arrayPush(result, symbolsFunc(object));
     }
 
     /**
@@ -4879,6 +4877,20 @@
       return new Set(values);
     };
 
+    /**
+     * Creates a `_.toPairs` or `_.toPairsIn` function.
+     *
+     * @private
+     * @param {Function} keysFunc The function to get the keys of a given object.
+     * @returns {Function} Returns the new pairs function.
+     */
+    function createToPairs(keysFunc) {
+      return function(object) {
+        var tag = getTag(object);
+        return tag == mapTag ? mapToArray(object) : baseToPairs(object, keysFunc(object));
+      };
+    }
+
     /**
      * Creates a function that either curries or invokes `func` with optional
      * `this` binding and partially applied arguments.
@@ -12893,9 +12905,7 @@
      * _.toPairs(new Foo);
      * // => [['a', 1], ['b', 2]] (iteration order is not guaranteed)
      */
-    function toPairs(object) {
-      return baseToPairs(object, keys(object));
-    }
+    var toPairs = createToPairs(keys);
 
     /**
      * Creates an array of own and inherited enumerable string keyed-value pairs
@@ -12920,9 +12930,7 @@
      * _.toPairsIn(new Foo);
      * // => [['a', 1], ['b', 2], ['c', 1]] (iteration order is not guaranteed)
      */
-    function toPairsIn(object) {
-      return baseToPairs(object, keysIn(object));
-    }
+    var toPairsIn = createToPairs(keysIn);
 
     /**
      * An alternative to `_.reduce`; this method transforms `object` to a new

test/test.js

@@ -23256,15 +23256,6 @@
       assert.deepEqual(actual, [['a', 1], ['b', 2]]);
     });
 
-    QUnit.test('`_.' + methodName + '` should work with an object that has a `length` property', function(assert) {
-      assert.expect(1);
-
-      var object = { '0': 'a', '1': 'b', 'length': 2 },
-          actual = lodashStable.sortBy(func(object), 0);
-
-      assert.deepEqual(actual, [['0', 'a'], ['1', 'b'], ['length', 2]]);
-    });
-
     QUnit.test('`_.' + methodName + '` should ' + (isToPairs ? 'not ' : '') + 'include inherited string keyed property values', function(assert) {
       assert.expect(1);
 
@@ -23279,7 +23270,30 @@
       assert.deepEqual(actual, expected);
     });
 
-    QUnit.test('`_.' + methodName + '` should work with strings', function(assert) {
+    QUnit.test('`_.' + methodName + '` should convert objects with a `length` property', function(assert) {
+      assert.expect(1);
+
+      var object = { '0': 'a', '1': 'b', 'length': 2 },
+          actual = lodashStable.sortBy(func(object), 0);
+
+      assert.deepEqual(actual, [['0', 'a'], ['1', 'b'], ['length', 2]]);
+    });
+
+    QUnit.test('`_.' + methodName + '` should convert maps', function(assert) {
+      assert.expect(1);
+
+      if (Map) {
+        var map = new Map;
+        map.set('a', 1);
+        map.set('b', 2);
+        assert.deepEqual(func(map), [['a', 1], ['b', 2]]);
+      }
+      else {
+        skipAssert(assert);
+      }
+    });
+
+    QUnit.test('`_.' + methodName + '` should convert strings', function(assert) {
       assert.expect(2);
 
       lodashStable.each(['xo', Object('xo')], function(string) {