egg-aop

[![NPM version][npm-image]][npm-url]
[![build status][travis-image]][travis-url]
[![Test coverage][codecov-image]][codecov-url]
[![David deps][david-image]][david-url]
[![Known Vulnerabilities][snyk-image]][snyk-url]
[![npm download][download-image]][download-url]

[npm-image]: https://img.shields.io/npm/v/egg-aop.svg?style=flat-square
[npm-url]: https://npmjs.org/package/egg-aop
[travis-image]: https://img.shields.io/travis/eggjs/egg-aop.svg?style=flat-square
[travis-url]: https://travis-ci.org/eggjs/egg-aop
[codecov-image]: https://codecov.io/github/eggjs/egg-aop/coverage.svg?branch=master
[codecov-url]: https://codecov.io/github/eggjs/egg-aop?branch=master
[david-image]: https://img.shields.io/david/eggjs/egg-aop.svg?style=flat-square
[david-url]: https://david-dm.org/eggjs/egg-aop
[snyk-image]: https://snyk.io/test/npm/egg-aop/badge.svg?style=flat-square
[snyk-url]: https://snyk.io/test/npm/egg-aop
[download-image]: https://img.shields.io/npm/dm/egg-aop.svg?style=flat-square
[download-url]: https://npmjs.org/package/egg-aop

Add DI, AOP support for eggjs.

DI

$3

``ts
import { Service, Context } from 'egg';
import { context, lazyInject } from 'egg-aop';

@context() // or @application()
export class TestService extends Service {
get() {
/ code /
}
}

export class Controller {
@lazyInject()
private testService: TestService;

demo() {
this.testService.get();
}
}
`

$3

#### decoratros
- @context(keyType?: any)

Declaration life cycle of instance, is context level. You can provide a class type or from metadata by TypeScript emit.

- @application(keyType?: any)

Declaration life cycle of instance, is context level. You can provide a class type or from metadata by TypeScript emit.

- @inject(keyType?: any)

Inject component when the class instantiation.

- @lazyInject(keyType?: any)

Inject component when access the property.

#### functions
- getInstance(clsType: any, app: any, ctx: any): T

You can use this function to manually get the component instance.

- setCreateInstanceHook(func: CreateInstanceHookFunction)

You can use this function to interception every new component instance.

type CreateInstanceHookFunction = (instance: any, app: any, ctx?: any) => any;

#### typeLoader

typeLoader is a instance of IocContext, this stored all type's classes. You can use this to affect DI behavior.

AOP

$3


`ts
function logging(type: string) {
return aspect({
// before method running
before: (context) => { / log code / },
// after method running
after: (context) => { / log code / },
// when method throw error
onError: (context) => { / log code / },
})
}

class DemoService {
@logging('create')
createData() {
/ code /
}
}

/ FunctionContext type define /
export interface FunctionContext {
readonly inst: T;
readonly functionName: string;
args: any[];
ret: any;
err: Error;
}
`

$3

#### functions
- aspect(point: AspectPoint = {})

You can use this to interception method, this function provide before / after / error cross-section.

`ts
interface AspectPoint {
before?: (context: FunctionContext) => void;
after?: (context: FunctionContext) => void;
error?: (context: FunctionContext) => void;
}
`

The param context is the function's execution context. It include inst / args / ret`. You can replace them to affect the function execute.