refactor: combine implementation of adding/removing hooks

index.js

@@ -1,30 +1,22 @@
 module.exports = Hook
 
 var register = require('./lib/register')
-var before = require('./lib/before')
-var error = require('./lib/error')
-var after = require('./lib/after')
-var removeBefore = require('./lib/remove-before')
-var removeError = require('./lib/remove-error')
-var removeAfter = require('./lib/remove-after')
+var addHook = require('./lib/add')
+var removeHook = require('./lib/remove')
 
 function Hook () {
  var state = {
  registry: {}
  }
 
  var hook = register.bind(null, state)
- hook.api = {}
+ hook.remove = {}
+ hook.api = {remove: {}}
 
- hook.api.before = hook.before = before.bind(null, state)
- hook.api.error = hook.error = error.bind(null, state)
- hook.api.after = hook.after = after.bind(null, state)
-
- hook.api.remove = hook.remove = {
- before: removeBefore.bind(null, state),
- error: removeError.bind(null, state),
- after: removeAfter.bind(null, state)
- }
+ ;['before', 'error', 'after'].forEach(function (kind) {
+ hook[kind] = hook.api[kind] = addHook.bind(null, state, kind)
+ hook.remove[kind] = hook.api.remove[kind] = removeHook.bind(null, state, kind)
+ })
 
  return hook
 }

lib/add.js

@@ -0,0 +1,13 @@
+module.exports = addHook
+
+function addHook (state, kind, name, hook) {
+ if (!state.registry[name]) {
+ state.registry[name] = {
+ before: [],
+ error: [],
+ after: []
+ }
+ }
+
+ state.registry[name][kind][kind === 'before' ? 'unshift' : 'push'](hook)
+}

lib/register.js

@@ -21,6 +21,7 @@ function register (state, name, options, method) {
  }
 
  var hooks = state.registry[name]
+
  if (!hooks) {
  return invokeMethod(options, method)
  }
@@ -29,12 +30,17 @@ function register (state, name, options, method) {
  var errorHooks = hooks.error
  var afterHooks = hooks.after
 
+ // 1. run "before hooks" which may mutate options
  return Promise.all(beforeHooks.map(invokeBeforeHook.bind(null, options)))
 
+ // 2. Once all finish without error, call the method with the (mutated) options
  .then(function () {
  return method(options)
  })
 
+ // 3. If an error occurs in 1. or 2. run the "error hooks" which may mutate
+ // the error object. If one of them does not return an error then set the
+ // result to that. Otherwise throw (mutated) error.
  .catch(function (error) {
  return Promise.all(errorHooks.map(invokeErrorHook.bind(null, error, options)))
 
@@ -49,6 +55,7 @@ function register (state, name, options, method) {
  })
  })
 
+ // 4. Run the "after hooks". They may mutate the result
  .then(function (result) {
  return Promise.all(afterHooks.map(invokeAfterHook.bind(null, result, options)))
 

lib/remove.js

@@ -0,0 +1,15 @@
+module.exports = removeHook
+
+function removeHook (state, kind, name, method) {
+ if (!state.registry[name]) {
+ return
+ }
+
+ var index = state.registry[name][kind].indexOf(method)
+
+ if (index === -1) {
+ return
+ }
+
+ state.registry[name][kind].splice(index, 1)
+}