New stateFor CP

addon/state-for.js

@@ -0,0 +1,80 @@
+import Ember from 'ember';
+
+var {
+  computed,
+  assert,
+  typeOf
+} = Ember;
+
+var states = {};
+
+/*
+* Create the states object for a given stateName.
+*
+* @param container {object} container to lookup the state factory on
+* @param stateName {string} state name which is also the name of the factory
+*/
+function createStates(container, stateName) {
+  let stateContainerName = `state:${stateName}`;
+  let StateFactory       = container.lookupFactory(stateContainerName);
+
+  if (!StateFactory) {
+    throw new TypeError(`Unknown StateFactory: \`${stateContainerName}\``);
+  }
+
+  states[stateName] = new Ember.MapWithDefault({
+    defaultValue: () => buildDefaultState.call(this, StateFactory)
+  });
+
+  return states[stateName];
+}
+
+/*
+* When creating the state instance we use `initialState` method
+* on the state class to build its initial state. If it not
+* specified then {} is used as the default state.
+*
+* @param Factory {StateFactoryClass} state factory from the container
+* @return {stateInstance} state instance object from the factory
+*/
+function buildDefaultState(Factory) {
+  let defaultState = {};
+
+  if (typeOf(Factory.initialState) === 'function') {
+    defaultState = Factory.initialState.call(this);
+  }
+
+  return Factory.create(defaultState);
+}
+
+/*
+* Returns a computed property that returns state based off of a dynamic key.
+*
+* @param stateName {string} name of the state factory which is located in /states/<stateName>.js
+* @param options {object}
+* @param {string} options.key - required - the dynamic state key
+* @param {object} options.container - optional - container reference
+* @return {computed property}
+*/
+export default function stateFor(stateName, options) {
+  var { key, container } = options;
+
+  assert(`
+    Missing \`key\` property within the second argument. You passed: ${JSON.stringify(options)}
+    `, key);
+
+  return computed(key, function() {
+    assert(`
+      Could not find the container on \`this\` or passed in via:
+      stateFor('${stateName}', { key: ${key}, container: <pass container here> })
+      `, this.container || container);
+
+    if (states[stateName]) {
+      return states[stateName].get(this.get(key));
+    }
+
+    return createStates
+              .apply(this, [container || this.container, stateName])
+              .get(this.get(key));
+  });
+}

tests/dummy/app/components/edit-email.js

@@ -1,11 +1,9 @@
 import Ember from 'ember';
+import stateFor from 'ember-state-services/state-for';
 
 export default Ember.Component.extend({
   tagName: 'form',
-  editEmailService: Ember.inject.service('edit-email'),
-  data: Ember.computed('email', function() {
-    return this.get('editEmailService').stateFor(this.get('email'));
-  }).readOnly(),
+  data: stateFor('edit-email', { key: 'email' }),
 
   actions: {
     save: function() {

tests/dummy/app/states/edit-email.js

@@ -1,3 +1,9 @@
 import BufferedProxy from 'ember-buffered-proxy/proxy';
 
+BufferedProxy.reopenClass({
+  initialState() {
+    return { content: this.get('email') };
+  }
+});
+
 export default BufferedProxy.extend();