Add batch callbacks

README.md

@@ -29,6 +29,7 @@ Example:
   * [Sequential & Parallel](#seqandpar)
   * [Sequence Parameters](#parameters)
   * [Ordered Parallel Paramters](#parpar)
+  * [Batch Callbacks](#batch)
   * [Unit Tests](#tests)
 
 ## <a name="small" />Small
@@ -90,6 +91,31 @@ Example:
       // function2[0] === 'Hello, World!'
     });
 
+## <a name="batch" />Batch Callbacks
+
+    first(function () {
+      // first do something
+      this();
+    }).
+    then(function () {
+      // then do something else
+      this();
+    }, function {
+      // then do something else
+      this();
+    }).
+    then(function () {
+      // then do something else
+      this();
+    }).
+    whilst(function () {
+      // whilst doing something else
+      this();
+    }, function () {
+      // whilst doing something else
+      this();
+    });
+
 ## <a name="tests" />Unit Tests
 
     make test

lib/first.js

@@ -1,6 +1,9 @@
 /*jshint eqeqeq:true, proto:true, laxcomma:true, undef:true, node:true, expr: true*/
 
-var slice = Array.prototype.slice, isArray = require('util').isArray;
+var slice = Array.prototype.slice
+  , isArray = require('util').isArray
+  , push = Array.prototype.push
+  , concat = Array.prototype.concat;
 
 module.exports = function first (f) {
   var functions = [f], next = function () {
@@ -43,16 +46,16 @@ module.exports = function first (f) {
   };
 
   var deferred = {
-    then: function(f) {
-      functions.push(f);
+    then: function() {
+      push.apply(functions, arguments);
       return this;
     },
-    whilst: function(f) {
+    whilst: function() {
       var last = functions.length-1;
       if (isArray (functions[last])) {
-        functions[last].push(f);
+        push.apply(functions[last], arguments);
       } else {
-        functions[last] = [functions[last], f];
+        functions[last] = concat.apply([functions[last]], arguments);
       }
       return this;
     }