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