Add Stack#size.

lodash.js

@@ -1900,8 +1900,8 @@
      * @memberOf Hash
      */
     function hashClear() {
-      this.size = 0;
       this.__data__ = nativeCreate ? nativeCreate(null) : {};
+      this.size = 0;
     }
 
     /**
@@ -2004,8 +2004,8 @@
      * @memberOf ListCache
      */
     function listCacheClear() {
-      this.size = 0;
       this.__data__ = [];
+      this.size = 0;
     }
 
     /**
@@ -2258,7 +2258,8 @@
      * @param {Array} [entries] The key-value pairs to cache.
      */
     function Stack(entries) {
-      this.__data__ = new ListCache(entries);
+      var data = this.__data__ = new ListCache(entries);
+      this.size = data.size;
     }
 
     /**
@@ -2270,6 +2271,7 @@
      */
     function stackClear() {
       this.__data__ = new ListCache;
+      this.size = 0;
     }
 
     /**
@@ -2282,7 +2284,11 @@
      * @returns {boolean} Returns `true` if the entry was removed, else `false`.
      */
     function stackDelete(key) {
-      return this.__data__['delete'](key);
+      var data = this.__data__,
+          result = data['delete'](key);
+
+      this.size = data.size;
+      return result;
     }
 
     /**
@@ -2322,16 +2328,18 @@
      * @returns {Object} Returns the stack cache instance.
      */
     function stackSet(key, value) {
-      var cache = this.__data__;
-      if (cache instanceof ListCache) {
-        var pairs = cache.__data__;
+      var data = this.__data__;
+      if (data instanceof ListCache) {
+        var pairs = data.__data__;
         if (!Map || (pairs.length < LARGE_ARRAY_SIZE - 1)) {
           pairs.push([key, value]);
+          this.size = ++data.size;
           return this;
         }
-        cache = this.__data__ = new MapCache(pairs);
+        data = this.__data__ = new MapCache(pairs);
       }
-      cache.set(key, value);
+      data.set(key, value);
+      this.size = data.size;
       return this;
     }
 
@@ -10343,7 +10351,7 @@
       return memoized;
     }
 
-    // Assign cache to `_.memoize`.
+    // Expose `MapCache`.
     memoize.Cache = MapCache;
 
     /**

test/test-fp.js

@@ -1309,7 +1309,7 @@
       var args,
           iteration = 0,
           objects = [{ 'a': 1 }, { 'a': 2 }],
-          stack = { '__data__': { '__data__': [objects, objects.slice().reverse()], 'size': 0 } },
+          stack = { '__data__': { '__data__': [objects, objects.slice().reverse()], 'size': 2 }, 'size': 2 },
           expected = [1, 2, 'a', objects[0], objects[1], stack];
 
       fp.isEqualWith(function() {
@@ -1335,7 +1335,7 @@
 
       var args,
           objects = [{ 'a': 1 }, { 'a': 2 }],
-          stack = { '__data__': { '__data__': [], 'size': 0 } },
+          stack = { '__data__': { '__data__': [], 'size': 0 }, 'size': 0 },
           expected = [2, 1, 'a', objects[1], objects[0], stack];
 
       fp.isMatchWith(function() {
@@ -1444,7 +1444,7 @@
       assert.expect(1);
 
       var args,
-          stack = { '__data__': { '__data__': [], 'size': 0 } },
+          stack = { '__data__': { '__data__': [], 'size': 0 }, 'size': 0 },
           expected = [[1, 2], [3], 'a', { 'a': [1, 2] }, { 'a': [3] }, stack];
 
       fp.mergeWith(function() {
@@ -1477,7 +1477,7 @@
       assert.expect(1);
 
       var args,
-          stack = { '__data__': { '__data__': [], 'size': 0 } },
+          stack = { '__data__': { '__data__': [], 'size': 0 }, 'size': 0 },
           expected = [[1, 2], [3], 'a', { 'a': [1, 2] }, { 'a': [3] }, stack];
 
       fp.mergeAllWith(function() {

test/test.js

@@ -1062,8 +1062,10 @@
     }
 
     lodashStable.forOwn(createCaches(pairs), function(cache, kind) {
+      var isLarge = /^large/.test(kind);
+
       QUnit.test('should implement a `Map` interface for ' + kind, function(assert) {
-        assert.expect(82);
+        assert.expect(83);
 
         lodashStable.each(keys, function(key, index) {
           var value = pairs[index][1];
@@ -1078,6 +1080,7 @@
           assert.strictEqual(cache.has(key), true);
         });
 
+        assert.strictEqual(cache.size, isLarge ? LARGE_ARRAY_SIZE : keys.length);
         assert.strictEqual(cache.clear(), undefined);
         assert.ok(lodashStable.every(keys, function(key) {
           return !cache.has(key);
@@ -1090,9 +1093,7 @@
         assert.expect(10);
 
         lodashStable.each(keys, function(key) {
-          cache.set(key, 1);
-          cache.set(key, 2);
-
+          cache.set(key, 1).set(key, 2);
           assert.strictEqual(cache.get(key), 2);
         });
       });