Add context.none() & group('none')

lib/stepdown.js

@@ -82,7 +82,7 @@ function alloc(type, hookFn) {
                 index += adj.amount;
             }
         });
-
+        
         if (self[index] !== NO_RESULT) {
             throw new Error('Callbacks cannot be reused.');
         }
@@ -114,6 +114,17 @@ function alloc(type, hookFn) {
                 index: index,
                 amount: arguments.length - 2
             });
+        } else if (type === 'none') {
+            self.splice(index, 1);
+            self.spreads.forEach(function (adj) {
+                if (adj.index > index) {
+                    adj.index -= 1;
+                }
+            });
+            self.spreads.push({
+                index: index,
+                amount: -1
+            });
         }
 
         self.expectedLength--;
@@ -276,6 +287,12 @@ function _defineProps() {
             value: function bindError(ee) {
                 return stepdown.bindError(ee, self);
             }
+        },
+        none: {
+            value: function none(hookFn) {
+                self._outOfSync();
+                return self.results.alloc('none', hookFn);
+            }
         }
     });
 }
@@ -366,7 +383,7 @@ function _group(count, type) {
     }
 
     var self = this,
-        callback = this.results.alloc('group'),
+        callback = this.results.alloc( type === 'none' ? 'none' : 'group'),
         groupResults = createResultSet(callback),
         group;
 
@@ -381,7 +398,7 @@ function _group(count, type) {
 
     process.nextTick(function () {
         if (!self.sync && !groupResults.length) {
-            callback(null, []);
+            callback(null, type === 'none' ? null : []);
         }
     });
 

test/stepdown.js

@@ -219,6 +219,9 @@ describe('Stepdown', function () {
                 context.push('event')(hits.concat([4]));
             }, function stepSix(context, hits) {
                 expect(hits.slice()).to.deep.equal([1, 2, 3, 4]);
+                context.push('none')(null, hits.concat([5]));
+            }, function stepSeven(context, hits) {
+                expect(arguments).to.have.length(1);
                 done();
             }]);
         });
@@ -233,9 +236,10 @@ describe('Stepdown', function () {
             }, function stepFour(context, hits, otherArray) {
                 context.collapse()(null, hits[0], hits[1], otherArray[0]);
             }, function stepFive(context, hits) {
-                context.event()(hits.concat([4]));
-            }, function stepSix(context, hits) {
-                expect(hits.slice()).to.deep.equal([1, 2, 3, 4]);
+                context.none()(null, hits.concat([4]));
+                context.event()(hits.concat([5]));
+            }, function stepSeven(context, hits) {
+                expect(hits.slice()).to.deep.equal([1, 2, 3, 5]);
                 done();
             }]);
         });
@@ -250,10 +254,11 @@ describe('Stepdown', function () {
             }, function stepFour(context, hits, otherArray) {
                 context.push('collapse')(null, hits[0], hits[1], otherArray[0]);
             }, function stepFive(context, hits) {
-                context.push('event')(hits.concat([4]));
+                context.push('none')(null, hits.concat([4]));
+                context.push('event')(hits.concat([5]));
             }], function finished(err, hits) {
                 expect(err).to.not.exist;
-                expect(hits.slice()).to.deep.equal([1, 2, 3, 4]);
+                expect(hits.slice()).to.deep.equal([1, 2, 3, 5]);
                 expect(arguments).to.have.length(2);
                 done();
             });
@@ -372,6 +377,13 @@ describe('Stepdown', function () {
                 callbacks[1](2);
             }, function stepSix(context, hits) {
                 expect(hits.slice()).to.deep.equal([1, 2]);
+
+                var callbacks = context.group(2, 'none');
+
+                callbacks[0](null, 1);
+                callbacks[1](null, 2, 3);
+            }, function stepSeven(context) {
+                expect(arguments.length).to.equal(1);
             }], done);
         });