Add new JS component API and improve the Redux API

app/assets/javascripts/miq_global.js

@@ -84,6 +84,7 @@ if (! window.ManageIQ) {
       debounced: {}, // running debounces
       debounce_counter: 1,
     },
-    redux: null // Redux API
+    redux: null, // initialized via 'miq-redux' pack
+    component: null // initialized via 'miq-component' pack
   };
 }

app/javascript/miq-component/component-typings.ts

@@ -0,0 +1,144 @@
+import { Unsubscribe } from 'redux';
+
+/**
+ * Component definition, serving as a blueprint to create new instances, as well
+ * as providing access to existing instances.
+ *
+ * Use the `create` method to create new instance and (optionally) mount it to
+ * the given DOM element, depending on whether the component requires DOM context.
+ *
+ * Note that the `create` method itself is optional - components may expose their
+ * existing instances without allowing further instantiation.
+ */
+export interface ComponentDefinition {
+
+  /**
+   * Name that reflects the component type (must be unique).
+   */
+  name: string;
+
+  /**
+   * Create new instance and (optionally) mount it to the given DOM element.
+   *
+   * @param props Used to initialize the component.
+   * @param mountTo DOM element to mount the component to.
+   * @param callback Callback for providing component instance.
+   *
+   * @returns Function to destroy (and unmount) the component.
+   */
+  create?(props?: any, mountTo?: HTMLElement, callback?: ComponentInstanceCallback): Unsubscribe;
+
+  /**
+   * Get instance of this component, as indicated by its `id`.
+   *
+   * @param id Instance `id` to lookup.
+   *
+   * @returns Component instance matching the `id` or `undefined` if there is
+   * no such instance.
+   */
+  getInstance(id: string): ComponentInstance | undefined;
+
+  /**
+   * Get all component instances.
+   *
+   * @returns Current snapshot of instances associated with this definition.
+   */
+  getAllInstances(): ComponentInstance[];
+
+}
+
+/**
+ * Component instance, identified (and lookup-able) by its `id` property.
+ *
+ * Each instance may provide an interface for interaction. For example,
+ * a navigational component might expose `addMenuItem` or similar methods.
+ * By convention, such interface should be represented by the `interact`
+ * property.
+ */
+export interface ComponentInstance {
+
+  /**
+   * Instance `id` is merely a way to distinguish individual component instances
+   * for better lookup - it's not guaranteed to be unique or follow any specific
+   * format.
+   *
+   * If not defined or not a string, its value will be auto-generated.
+   */
+  id: string;
+
+  /**
+   * Interface for component interaction (optional).
+   *
+   * The value is entirely component specific.
+   */
+  interact?: any;
+
+}
+
+/**
+ * Blueprint used to create and destroy component instances.
+ */
+export interface ComponentBlueprint {
+
+  /**
+   * Just like the `ComponentDefinition.create` method, minus the cleanup part.
+   *
+   * This method *must* return an object that satisfies the `ComponentInstance`
+   * interface. Otherwise, the `ComponentDefinition.create` method will throw
+   * an error that indicates a problem with the blueprint.
+   *
+   * Note that the returned instance will be sanitized (e.g. ensure proper `id`
+   * value) prior to adding it to the instance collection.
+   */
+  create?(props?: any, mountTo?: HTMLElement): ComponentInstance;
+
+  /**
+   * Destroy `instance` and unmount it from the given DOM element as necessary.
+   */
+  destroy?(instance?: ComponentInstance, mountFrom?: HTMLElement): void;
+
+}
+
+/**
+ * Callback used to provide the component instance.
+ */
+export type ComponentInstanceCallback = (instance: ComponentInstance) => void;
+
+/**
+ * `ManageIQ.component` API.
+ */
+export interface ComponentApi {
+
+  /**
+   * Define new component.
+   *
+   * Each component has a unique `name`. Attempts to define new component with
+   * an already taken `name` will have no effect.
+   *
+   * @param name Component name (must be unique).
+   * @param blueprint Blueprint used to create and destroy component instances.
+   * @param instances Existing instances to associate with this definition.
+   *
+   * @returns Definition of the new component or `undefined` if the provided
+   * `name` is already taken.
+   */
+  define(name: string, blueprint: ComponentBlueprint, instances?: ComponentInstance[]): ComponentDefinition | undefined;
+
+  /**
+   * Get definition of a component, as indicated by its `name`.
+   *
+   * @param name Component `name` to lookup.
+   *
+   * @returns Component definition matching the `name` or `undefined` if there
+   * is no such definition.
+   */
+  getDefinition(name: string): ComponentDefinition | undefined;
+
+  /**
+   * Get all component definitions.
+   *
+   * @returns Current snapshot of all component definitions.
+   */
+  getAllDefinitions(): ComponentDefinition[];
+
+}

app/javascript/miq-component/index.ts

@@ -0,0 +1,28 @@
+import { IModule } from 'angular';
+
+import {
+  sanitizeInstance, instanceCreatorFactory,
+  define, getDefinition, getAllDefinitions,
+  clearRegistry
+} from './registry';
+
+export default (app: IModule): void => {
+  // allow unit-testing specific module exports
+  if (window['jasmine']) {
+    app.constant('_component_units', {
+      sanitizeInstance,
+      instanceCreatorFactory,
+      define,
+      getDefinition,
+      getAllDefinitions,
+      clearRegistry
+    });
+  }
+
+  // initialize the namespace (don't wait for application startup)
+  ManageIQ.component = {
+    define,
+    getDefinition,
+    getAllDefinitions
+  };
+};

app/javascript/miq-component/registry.ts

@@ -0,0 +1,110 @@
+import { Unsubscribe } from 'redux';
+
+import { ComponentDefinition, ComponentInstance, ComponentBlueprint, ComponentInstanceCallback } from './component-typings';
+
+const registry: Map<ComponentDefinition, Set<ComponentInstance>> = new Map();
+
+/**
+ * Sanitize `instance` properties, as defined by the `ComponentInstance` interface.
+ */
+export function sanitizeInstance(instance: ComponentInstance, definition: ComponentDefinition): void {
+  if (typeof instance.id !== 'string') {
+    instance.id = `${definition.name}-${definition.getAllInstances().length}`;
+  }
+}
+
+/**
+ * Provides `ComponentDefinition.create` method implementations.
+ */
+export function instanceCreatorFactory(definition: ComponentDefinition, blueprint: ComponentBlueprint):
+  (props: any, mountTo: HTMLElement, callback: ComponentInstanceCallback) => Unsubscribe {
+  return (props, mountTo, callback) => {
+    // construct
+    const newInstance = blueprint.create(props, mountTo);
+
+    // validate
+    if (!newInstance) {
+      throw new Error(`blueprint.create returned falsy value during ${definition.name} instance creation`);
+    }
+
+    // sanitize
+    sanitizeInstance(newInstance, definition);
+
+    // add instance to the registry
+    registry.get(definition).add(newInstance);
+
+    // provide instance through callback
+    typeof callback === 'function' && callback(newInstance);
+
+    return () => {
+      // destroy
+      typeof blueprint.destroy === 'function' && blueprint.destroy(newInstance, mountTo);
+
+      // remove instance from the registry
+      registry.get(definition).delete(newInstance);
+    };
+  }
+}
+
+/**
+ * Implements `ComponentApi.define` method.
+ */
+export function define(name: string, blueprint: ComponentBlueprint, instances?: ComponentInstance[]): ComponentDefinition | undefined {
+  if (typeof name !== 'string' || !blueprint || getDefinition(name) !== undefined) {
+    return;
+  }
+
+  const getAllInstances = () => Array.from(registry.get(newDefinition));
+
+  // create component definition
+  const newDefinition: ComponentDefinition = {
+    name,
+    getInstance: (id: string) => getAllInstances().find(instance => instance.id === id),
+    getAllInstances
+  };
+
+  // add instance creator, if supported by the blueprint
+  if (typeof blueprint.create === 'function') {
+    newDefinition.create = instanceCreatorFactory(newDefinition, blueprint);
+  }
+
+  // add definition to the registry
+  registry.set(newDefinition, new Set());
+
+  // add existing instances to the registry
+  if (Array.isArray(instances)) {
+    instances.forEach(instance => {
+      if (instance) {
+        sanitizeInstance(instance, newDefinition);
+        registry.get(newDefinition).add(instance);
+      }
+    });
+  }
+
+  return newDefinition;
+}
+
+/**
+ * Implements `ComponentApi.getDefinition` method.
+ */
+export function getDefinition(name: string): ComponentDefinition | undefined {
+  return getAllDefinitions().find(definition => definition.name === name);
+}
+
+/**
+ * Implements `ComponentApi.getAllDefinitions` method.
+ */
+export function getAllDefinitions(): ComponentDefinition[] {
+  return Array.from(registry.keys());
+}
+
+/**
+ * Remove all component data.
+ *
+ * Does not call `blueprint.destroy` for existing instances.
+ *
+ * *For testing purposes only.*
+ */
+export function clearRegistry(): void {
+  registry.clear();
+}

app/javascript/miq-redux/index.ts

@@ -1,26 +1,28 @@
+import { IModule } from 'angular';
+
 import { configureNgReduxStore } from './store';
 import { rootReducer, addReducer, clearReducers, applyReducerHash } from './reducer';
 
-const app = ManageIQ.angular.app;
-
-const initialState = {};
-
-// configure Angular application to use ng-redux
-configureNgReduxStore(app, initialState);
+export default (app: IModule): void => {
+  // allow unit-testing specific module exports
+  if (window['jasmine']) {
+    app.constant('_redux_units', {
+      rootReducer,
+      addReducer,
+      clearReducers,
+      applyReducerHash
+    });
+  }
 
-// allow unit-testing specific module exports
-if (window['jasmine']) {
-  app.constant('_rootReducer', rootReducer);
-  app.constant('_addReducer', addReducer);
-  app.constant('_clearReducers', clearReducers);
-  app.constant('_applyReducerHash', applyReducerHash);
-}
+  // configure Angular application to use ng-redux
+  configureNgReduxStore(app, {});
 
-// initialize Redux namespace upon application startup
-app.run(['$ngRedux', ($ngRedux) => {
-  ManageIQ.redux = {
-    store: $ngRedux,
-    addReducer,
-    applyReducerHash
-  };
-}]);
+  // initialize the namespace upon application startup
+  app.run(['$ngRedux', ($ngRedux) => {
+    ManageIQ.redux = {
+      store: $ngRedux,
+      addReducer,
+      applyReducerHash
+    };
+  }]);
+};

app/javascript/miq-redux/reducer.ts

@@ -1,5 +1,4 @@
 import { Unsubscribe } from 'redux';
-
 import { AppState, AppReducer, Action, AppReducerHash } from './redux-typings';
 
 const reducers: Set<AppReducer> = new Set();

app/javascript/miq-redux/store.ts

@@ -1,9 +1,9 @@
 import { IModule } from 'angular';
-import { devToolsEnhancer, EnhancerOptions } from 'redux-devtools-extension/logOnlyInProduction';
+import { AppState } from './redux-typings';
 
+import { devToolsEnhancer, EnhancerOptions } from 'redux-devtools-extension/logOnlyInProduction';
 import { rootReducer } from './reducer';
 import { middlewares } from './middleware';
-import { AppState } from './redux-typings';
 
 const devToolsOptions: EnhancerOptions = {};
 

app/javascript/packs/application-common.js

@@ -6,3 +6,14 @@
 //
 // To reference this file, add <%= javascript_pack_tag 'application' %> to the appropriate
 // layout file, like app/views/layouts/application.html.erb
+
+import miqRedux from 'miq-redux';
+import miqComponent from 'miq-component';
+
+const app = ManageIQ.angular.app;
+
+// TODO(vs) link to article at http://talk.manageiq.org/c/developers
+miqRedux(app);
+
+// TODO(vs) link to article at http://talk.manageiq.org/c/developers
+miqComponent(app);