length, clone, and copy

lib/hash.js

@@ -2,17 +2,6 @@ module.exports = Hash;
 var Traverse = require('traverse');
 
 function Hash (hash, extra) {
-    if (extra == 'clone') { // deep copy
-        hash = Traverse.clone(hash);
-    }
-    else if (extra == 'copy') {
-        var acc = { __proto__ : hash.__proto__ };
-        Object.keys(hash).forEach(function (key) {
-            acc[key] = hash[key];
-        });
-        hash = acc;
-    }
-
     var self = {
         map : function (f) {
             var acc = { __proto__ : hash.__proto__ };
@@ -75,9 +64,35 @@ function Hash (hash, extra) {
             .map(function (key) { return hash[key] })
     } });
 
+    Object.defineProperty(self, 'clone', { get : function () {
+        return Hash(Hash.clone(hash));
+    } });
+
+    Object.defineProperty(self, 'copy', { get : function () {
+        return Hash(Hash.copy(hash));
+    } });
+
+    Object.defineProperty(self, 'length', { get : function () {
+        return Object.keys(hash).length;
+    } });
+
     return self;
 };
 
+// deep copy
+Hash.clone = function (ref) {
+    return Traverse.clone(ref);
+};
+
+// shallow copy
+Hash.copy = function (ref) {
+    var hash = { __proto__ : ref.__proto__ };
+    Object.keys(ref).forEach(function (key) {
+        hash[key] = ref[key];
+    });
+    return hash;
+};
+
 Hash.map = function (ref, f) {
     return Hash(ref).map(f).items;
 };

test/hash.js

@@ -11,7 +11,9 @@ exports['hash traversal'] = function (assert) {
     assert.equal(hash1.b, 3);
 
     var ref2 = { foo : [1,2], bar : [4,5] };
-    var hash2 = Hash.map(ref2, function (v) { v.unshift(v[0] - 1); return v });
+    var hash2 = Hash(ref2).clone.map(
+        function (v) { v.unshift(v[0] - 1); return v }
+    ).items;
     assert.equal(ref2.foo.join(' '), '1 2');
     assert.equal(ref2.bar.join(' '), '4 5');
     assert.equal(hash2.foo.join(' '), '0 1 2');