eventflow - npm Package Compare versions

Comparing version 0.0.8 to 0.0.9

eventflow.js

@@ -14,3 +14,3 @@ var async = require('async'),
   // Attach async methods.
-  ['series', 'parallel'].forEach(function(method) {
+  ['series', 'parallel', 'waterfall'].forEach(function(method) {
     eventEmitter[method] = function () {
@@ -21,3 +21,3 @@ var emitter = this,
           callback = args.pop(),
-          tasks = mapHandlers(emitter, name, args);
+          tasks = mapHandlers(method, emitter, name, args);
 
@@ -66,2 +66,3 @@ async[method](tasks, callback);
 function asyncApply (thisArg, fn, args, done) {
+  if (!Array.isArray(args)) args = [args];
   if (fn.length <= args.length) {
@@ -71,10 +72,14 @@ done(null, fn.apply(thisArg, args));
   else {
-    fn.apply(thisArg, args.slice(0).concat([done]));
+    fn.apply(thisArg, args.slice().concat(done));
   }
 }
 
-function mapHandlers (emitter, name, args) {
-  return emitter.listeners(name).map(function (listener) {
+function mapHandlers (method, emitter, name, args) {
+  return emitter.listeners(name).map(function (listener, idx) {
+    if (method === 'waterfall' && idx > 0) {
+      // For waterfall, args only need to be bound to the first task.
+      return asyncApply.bind(emitter, emitter, listener);
+    }
     return asyncApply.bind(emitter, emitter, listener, args);
   });
 }

package.json

 {
   "name": "eventflow",
-  "version": "0.0.8",
+  "version": "0.0.9",
   "description": "Flow control for your event emitters",
@@ -5,0 +5,0 @@ "main": "eventflow.js",

README.md

@@ -153,3 +153,23 @@ EventFlow
 
+Waterfall
+---------
 
+The waterfall method allows listeners to modify a variable in a series. The
+first listener receives an initial value, and each subsequent listener modifies
+the return of the last listener:
+
+```js
+emitter.on('foo', function(n) {
+  // sync task
+  return n + 1;
+});
+emitter.on('foo', function(n, callback) {
+  // async task
+  cb(null, n * 3);
+});
+emitter.waterfall('foo', 2, function(err, n) {
+  // n = 9
+});
+```
+
 - - -
@@ -156,0 +176,0 @@

test/basic.js

@@ -231,1 +231,44 @@ var eventflow = require('../'),
 
+describe('waterfall', function() {
+  var emitter;
+
+  beforeEach(function() {
+    emitter = new EventEmitter();
+  });
+
+  it('should pass a value between handlers', function (done) {
+    emitter.on('foo', function (n) {
+      return n + 1;
+    });
+
+    emitter.on('foo', function (n, cb) {
+      cb(null, n * 5);
+    });
+
+    emitter.on('foo', function (n) {
+      return n - 3;
+    });
+
+    emitter.waterfall('foo', 0, function (err, n) {
+      assert.equal(n, 2);
+      done();
+    });
+  });
+
+  it('should support optional use of `error`', function (done) {
+    emitter.on('drink', function (n) {
+      return n + 1;
+    });
+    emitter.on('drink', function (n, cb) {
+      cb('oh no!');
+    });
+    emitter.on('drink', function (n) {
+      return n - 3;
+    });
+    emitter.waterfall('drink', 0, function (err, n) {
+      assert.equal(n, undefined);
+      assert.equal(err, 'oh no!');
+      done();
+    });
+  });
+});

No alert changes

Improved metrics

Total package byte prevSize

15886

increased by11.22%

Lines of code

335

increased by14.33%

Number of lines in readme file

201

increased by11.05%

No dependency changes