add init lifecycle method to custom registries that receives the un…

…dertaker instance - closes #25

README.md

@@ -147,6 +147,7 @@ or add custom functionality to your registries.
 
 A registry's prototype should define:
 
+- `init(taker)`: receives the undertaker instance to set pre-defined tasks using the `task(taskName, fn)` method.
 - `get(taskName)`: returns the task with that name
    or `undefined` if no task is registered with that name.
 - `set(taskName, fn)`: add task to the registry. If `set` modifies a task, it should return the new task.
@@ -171,8 +172,11 @@ module.exports = MyRegistry;
 
 ### Sharing tasks
 
-To share common tasks with all your projects, you can set a registry with those
-tasks defined inside the constructor. For example you might want to share a `clean` task:
+To share common tasks with all your projects, you can expose an `init` method on the registry
+prototype and it will receive the Undertaker instance as the only argument. You can then use
+`undertaker.task(name, fn)` to register pre-defined tasks.
+
+For example you might want to share a `clean` task:
 
 ```javascript
 var fs = require('fs');
@@ -181,23 +185,29 @@ var util = require('util');
 var DefaultRegistry = require('undertaker-registry');
 var del = require('del');
 
-function CommonRegistry(){
+function CommonRegistry(opts){
   DefaultRegistry.call(this);
 
-  var buildDir = './build';
+  opts = opts || {};
+
+  this.buildDir = opts.buildDir || './build';
+}
+
+util.inherits(CommonRegistry, DefaultRegistry);
+
+CommonRegistry.prototype.init = function(takerInst){
+  var buildDir = this.buildDir;
   var exists = fs.existsSync(buildDir);
 
   if(exists){
-    throw new Error('Cannot initialize common tasks. `build/` directory exists.');
+    throw new Error('Cannot initialize common tasks. ' + buildDir + ' directory exists.');
   }
 
-  this.set('clean', function(cb){
+  takerInst.task('clean', function(cb){
     del([buildDir], cb);
   });
 }
 
-util.inherits(CommonRegistry, DefaultRegistry);
-
 module.exports = CommonRegistry;
 ```
 
@@ -206,7 +216,7 @@ Then to use it in a project:
 var Undertaker = require('undertaker');
 var CommonRegistry = require('myorg-common-tasks');
 
-var taker = new Undertaker(CommonRegistry);
+var taker = new Undertaker(CommonRegistry({ buildDir: '/dist' }));
 
 taker.task('build', taker.series('clean', function build(cb) {
   // do things

index.js

@@ -13,18 +13,16 @@ var parallel = require('./lib/parallel');
 var registry = require('./lib/registry');
 var _getTask = require('./lib/get-task');
 var _setTask = require('./lib/set-task');
-var validateRegistry = require('./lib/helpers/validateRegistry');
 
-function Undertaker(Registry){
+function Undertaker(customRegistry){
   EventEmitter.call(this);
 
-  Registry = Registry || DefaultRegistry;
-
-  this._registry = new Registry();
+  this._registry = new DefaultRegistry();
+  if(customRegistry){
+    this.registry(customRegistry);
+  }
 
   this._settle = (process.env.UNDERTAKER_SETTLE === 'true');
-
-  validateRegistry(this._registry);
 }
 
 inherits(Undertaker, EventEmitter);

lib/helpers/validateRegistry.js

@@ -4,10 +4,36 @@ var assert = require('assert');
 
 var _ = require('lodash');
 
+function isConstructor(registry){
+  if(!(registry && registry.prototype)){
+    return false;
+  }
+
+  var hasProtoGet = _.isFunction(registry.prototype.get);
+  var hasProtoSet = _.isFunction(registry.prototype.set);
+  var hasProtoInit = _.isFunction(registry.prototype.init);
+  var hasProtoTasks = _.isFunction(registry.prototype.tasks);
+
+  if(hasProtoGet || hasProtoSet || hasProtoInit || hasProtoTasks){
+    return true;
+  }
+
+  return false;
+}
+
 function validateRegistry(registry){
-  assert(_.isFunction(registry.get), 'Custom registry must have `get` function');
-  assert(_.isFunction(registry.set), 'Custom registry must have `set` function');
-  assert(_.isFunction(registry.tasks), 'Custom registry must have `tasks` function');
+  try {
+    assert(_.isFunction(registry.get), 'Custom registry must have `get` function');
+    assert(_.isFunction(registry.set), 'Custom registry must have `set` function');
+    assert(_.isFunction(registry.init), 'Custom registry must have `init` function');
+    assert(_.isFunction(registry.tasks), 'Custom registry must have `tasks` function');
+  } catch (err) {
+    if(isConstructor(registry)){
+      assert(false, 'Custom registries must be instantiated, but it looks like you passed a constructor');
+    } else {
+      throw err;
+    }
+  }
 }
 
 module.exports = validateRegistry;

lib/registry.js

@@ -6,6 +6,7 @@ var validateRegistry = require('./helpers/validateRegistry');
 
 function setTasks(inst, task, name){
   inst.set(name, task);
+  return inst;
 }
 
 function registry(newRegistry){
@@ -18,7 +19,8 @@ function registry(newRegistry){
 
   var tasks = this._registry.tasks();
 
-  this._registry = _.transform(tasks, setTasks, newRegistry);
+  this._registry = _.reduce(tasks, setTasks, newRegistry);
+  this._registry.init(this);
 }
 
 module.exports = registry;

package.json

@@ -25,7 +25,7 @@
     "es6-weak-map": "^1.0.1",
     "last-run": "^1.1.0",
     "lodash": "^3.5.0",
-    "undertaker-registry": "0.0.2"
+    "undertaker-registry": "0.0.3"
   },
   "devDependencies": {
     "async-once": "^1.0.0",
@@ -36,8 +36,8 @@
     "once": "^1.3.1",
     "promised-del": "^1.0.2",
     "through2": "^0.6.3",
-    "undertaker-common-tasks": "git://github.com/phated/undertaker-common-tasks#3d3a89ce66cf7397bb00ea9924e12e07db3bf987",
-    "undertaker-task-metadata": "git://github.com/undertakerjs/undertaker-task-metadata#eb02af6139fcf51a8abb5b7b76a993744512d69d",
+    "undertaker-common-tasks": "git://github.com/phated/undertaker-common-tasks",
+    "undertaker-task-metadata": "git://github.com/undertakerjs/undertaker-task-metadata",
     "vinyl-fs": "^1.0.0"
   },
   "keywords": [

test/registry.js

@@ -15,6 +15,7 @@ var MetadataRegistry = require('undertaker-task-metadata');
 function noop(){}
 
 function CustomRegistry(){}
+CustomRegistry.prototype.init = noop;
 CustomRegistry.prototype.get = noop;
 CustomRegistry.prototype.set = noop;
 CustomRegistry.prototype.tasks = noop;
@@ -52,7 +53,7 @@ describe('registry', function(){
     });
 
     it('should transfer all tasks from old registry to new', function(done){
-      var taker = new Undertaker(CommonRegistry);
+      var taker = new Undertaker(new CommonRegistry());
       var customRegistry = new DefaultRegistry();
       taker.registry(customRegistry);
 
@@ -83,12 +84,40 @@ describe('registry', function(){
 
       taker.series('context')();
     });
+
+    it('throws with a descriptive method when constructor is passed', function(done){
+      var taker = new Undertaker();
+
+      function ctor(){
+        taker.registry(CommonRegistry);
+      }
+
+      expect(ctor).to.throw(Error, 'Custom registries must be instantiated, but it looks like you passed a constructor');
+      done();
+    });
+
+    it('calls into the init function after tasks are transferred', function(done){
+      var taker = new Undertaker(new CommonRegistry());
+
+      var ogInit = DefaultRegistry.prototype.init;
+
+      DefaultRegistry.prototype.init = function(inst){
+        expect(inst).to.equal(taker);
+        expect(inst.task('clean')).to.be.a.function();
+        expect(inst.task('serve')).to.be.a.function();
+      };
+
+      taker.registry(new DefaultRegistry());
+
+      DefaultRegistry.prototype.init = ogInit;
+      done();
+    });
   });
 
   describe('constructor', function(){
 
-    it('should take a custom registry constructor on instantiation', function(done){
-      var taker = new Undertaker(CustomRegistry);
+    it('should take a custom registry on instantiation', function(done){
+      var taker = new Undertaker(new CustomRegistry());
       expect(taker.registry()).to.be.an.instanceof(CustomRegistry);
       expect(taker.registry()).to.not.be.an.instanceof(DefaultRegistry);
       done();
@@ -102,7 +131,7 @@ describe('registry', function(){
     });
 
     it('should take a registry that pre-defines tasks', function(done){
-      var taker = new Undertaker(CommonRegistry);
+      var taker = new Undertaker(new CommonRegistry());
       expect(taker.registry()).to.be.an.instanceof(CommonRegistry);
       expect(taker.registry()).to.be.an.instanceof(DefaultRegistry);
       expect(taker.task('clean')).to.be.a.function();
@@ -115,27 +144,34 @@ describe('registry', function(){
       var taker;
 
       function noGet(){
-        taker = new Undertaker(InvalidRegistry);
+        taker = new Undertaker(new InvalidRegistry());
       }
 
       expect(noGet).to.throw(Error, 'Custom registry must have `get` function');
       InvalidRegistry.prototype.get = noop;
 
       function noSet(){
-        taker = new Undertaker(InvalidRegistry);
+        taker = new Undertaker(new InvalidRegistry());
       }
 
       expect(noSet).to.throw(Error, 'Custom registry must have `set` function');
       InvalidRegistry.prototype.set = noop;
 
+      function noInit(){
+        taker = new Undertaker(new InvalidRegistry());
+      }
+
+      expect(noInit).to.throw(Error, 'Custom registry must have `init` function');
+      InvalidRegistry.prototype.init = noop;
+
       function noTasks(){
-        taker = new Undertaker(InvalidRegistry);
+        taker = new Undertaker(new InvalidRegistry());
       }
 
       expect(noTasks).to.throw(Error, 'Custom registry must have `tasks` function');
       InvalidRegistry.prototype.tasks = noop;
 
-      taker = new Undertaker(InvalidRegistry);
+      taker = new Undertaker(new InvalidRegistry());
       done();
     });
   });