ng-classified v1.0.2

ng-classified

Compels AngularJS to be friendly to ES6/ES2015 classes. It will be sweet to these fellows from now on.

Description

Wouldn't it be great to benefit from OOP application design and do something like this?

app.directive('appDirective', AppDirectiveClass);

Yes. And... no. This will cause the exception to be thrown right in developer's face. Depending on ES6 implementation, it may be

TypeError: Cannot call a class as a function

for Babel transpiler, or similar killjoy for Traceur and any JavaScript engine with native ES6 class support. That's right, class constructors should be newed. They cannot be called directly, but that's what $injector.invoke is trying to do. Bad injector, stupid invoke.

Naturally, the code above will end up as

app.directive('appDirective', (() => {
		let fn = (...deps) => new AppDirectiveClass(...deps);
		fn.$inject = AppDirectiveClass.$inject;
		return fn;
	})()
);

Wouldn't it be great to pollute the application with WET boilerplate wrapper hacks? Yes? Or... no?

This extension patches Angular $injector service in polite but urgent manner to give ES6 classes the treatment they deserve.

Install

NPM

npm install --save ng-classified

Bower

bower install --save ng-classified

Classified documentation

Relying on several conditions, $injector.invoke (which stands behind all DI in Angular) detects if the supplied function is a class constructor and should be called with new, not directly. Wraps the call to invoked function with try…catch, if necessary. It does all magic when Angular components are defined.

Annotation

As with functions, $inject static property is used to annotate class constructor.

static $inject = […] (ES7). Or ClassName.$inject = […] (ES6).

The dependencies will be annotated automatically in unminified code. Array annotations are not supported intentionally.

$classify property

$classify static property should be defined on classes in order for the injector to detect them unambiguously.

static $classify = true (ES7). Or ClassName.$classify = true (ES6).

Native (non-transpiled) Chrome/V8 classes can be certainly detected and don't need this property.

$classify service

Initially defines the behaviour of ngClassified module within application. It is not defined by default (assumed to be undefined) and supposed to be constant service to be ready-to-serve at configuration phase.

app.constant('$classify', true);

Possible values are:

• undefined (default). Provides heuristic approach to class detection (tries-catches only the functions which are believed to be class constructors). Suitable for production and unminified code.
• false. Detects native Chrome/V8 classes, relies on $classify property otherwise. Suitable for production and minified code.
• true. Tries-catches everything, provides considerable performance penalty. Suitable for development and minified code.

Clearance

TS. No pun intended.

Usage

The usage for average ES6/ES7 project is

import { ngClassified } from 'ng-classified';
import { JoeConfig } from 'joe-config';
import { JoeController } from 'joe-controller';
import { JoeDirective } from 'joe-directive';

angular.module('average', [ngClassified])
.constant('$classify', false)
.config(JoeConfig)
.controller('JoeController', JoeController)
.directive('joeDirective', JoeDirective);

export class JoeConfig {
	static $classify = true;

	constructor(averageUnannotatedProvider) {
		…
	}
}

export class JoeController {
	static $classify = true;

	scopeProperty = { … };  
}

export class JoeDirective {
	static $classify = true;
	static $inject = ['dependency'];

	constructor(...deps) {
		let depNames = this.constructor.$inject;

		Object.defineProperty(this, '$', {
			value: {}
		});

		depNames.forEach((depName, i) => {
			this.$[depName] = deps[i]; 
		});
	}

	scope = {};

	controller = 'JoeController';

	controllerAs = 'Joe';

	link = () => {
		this.$.dependency…;
	}
}

See also specs for more details on the use.

Compatibility

The extension itself doesn't use specific ES6 features. ES5 Function.prototype.bind is being used, it has to be be shimmed in PhantomJS and legacy browsers.