Merge a5677f2 into e45e3c4

README.md

@@ -40,7 +40,8 @@ Initialize a new `barracks` instance.
 Register a new action. Checks for circular dependencies when dispatching.  The
 callback receives the passed in data and a `wait(actions[, cb])` function that
 can be used to call other actions internally. `wait()` accepts a single action
-or an array of actions and an optional callback as the final argument.
+or an array of actions and an optional callback as the final argument.  Only
+one callback can be added per action.
 
 ### dispatcher(action[, data])
 Call an action and execute the corresponding callback. Alias:
@@ -96,7 +97,7 @@ pleased with, so I'll probably end up writing one in the near future.
 
 ## See Also
 - [flux-standard-action](https://github.com/acdlite/flux-standard-action/) - human-friendly standard for Flux action objects
-- [create-fsa](https://github.com/yoshuawuyts/create-fsa/) - create a flux-standard-action from a value 
+- [create-fsa](https://github.com/yoshuawuyts/create-fsa/) - create a flux-standard-action from a value
 - [wayfarer](https://github.com/yoshuawuyts/wayfarer) - composable trie based router
 
 ## License

index.js

@@ -22,6 +22,7 @@ function dispatcher () {
     assert.equal(typeof cb, 'function')
 
     actions[action] = actions[action] ? actions[action] : []
+    assert.equal(actions[action].length, 0, 'only on callback per action')
     actions[action].push(cb)
 
     return emit

package.json

@@ -23,7 +23,7 @@
   "devDependencies": {
     "coveralls": "~2.10.0",
     "istanbul": "~0.2.10",
-    "standard": "^4.5.4",
+    "standard": "^7.1.2",
     "tape": "^3.0.3",
     "watch": "^0.16.0"
   },

test.js

@@ -9,14 +9,25 @@ test('.on() should assert input arguments', function (t) {
 })
 
 test('.on() should bind functions', function (t) {
-  t.plan(3)
+  t.plan(2)
   const d = barracks()
   const key = 'foo'
   d.on(key, noop)
   t.ok(Array.isArray(d._actions[key]), 'is array')
   t.equal(d._actions[key].length, 1)
-  d.on('foo', noop)
-  t.equal(d._actions[key].length, 2)
+})
+
+test('.on() should only bind one function', function (t) {
+  t.plan(4)
+  const d = barracks()
+  const key = 'foo'
+  d.on(key, noop)
+  t.ok(Array.isArray(d._actions[key]), 'is array')
+  t.equal(d._actions[key].length, 1)
+  t.throws(function () {
+    d.on('foo', noop)
+  })
+  t.equal(d._actions[key].length, 1)
 })
 
 test('.emit() should assert action exists', function (t) {