@toss/nestjs-aop

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Table of Contents

1. Installation


2. Usage


3. Caveats


4. References


5. Contributing


6. License

Installation

``sh
npm install @toss/nestjs-aop
pnpm add @toss/nestjs-aop
yarn add @toss/nestjs-aop
`





Usage

#### 1. Import AopModule
`typescript
@Module({
imports: [
// ...
AopModule,
],
})
export class AppModule {}
`

#### 2. Create symbol for LazyDecorator
`typescript
export const CACHE_DECORATOR = Symbol('CACHE_DECORATOR');
`

#### 3. Implement LazyDecorator using nestjs provider
metadata is the second parameter of createDecorator.

`typescript
@Aspect(CACHE_DECORATOR)
export class CacheDecorator implements LazyDecorator {
constructor(private readonly cache: Cache) {}

wrap({ method, metadata: options }: WrapParams) {
return (...args: any) => {
let cachedValue = this.cache.get(...args);
if (!cachedValue) {
cachedValue = method(...args);
this.cache.set(cachedValue, ...args);
}
return cachedValue;
};
}
}
`

#### 4. Add LazyDecoratorImpl to providers of module
`typescript
@Module({
providers: [CacheDecorator],
})
export class CacheModule {}
`

#### 5. Create decorator that marks metadata of LazyDecorator
options can be obtained from the warp method and used.

`typescript
export const Cache = (options: CacheOptions) => createDecorator(CACHE_DECORATOR, options)
`

#### 6. Use it!
`typescript
export class SomeService {
@Cache({
// ...options(metadata value)
})
some() {
// ...
}
}
`





Caveats

If you’re testing with NestJS’s TestingModule, don’t forget to call the init method.

`typescript
import { Test } from '@nestjs/testing';

const module = await Test.createTestingModule({
// ...
}).compile();

await module.init();
``

References

- https://toss.tech/article/nestjs-custom-decorator
- https://youtu.be/VH1GTGIMHQw?t=2973

Contributing

We welcome contribution from everyone in this project. Read CONTRIBUTING.md for detailed contribution guide.

License

MIT © Viva Republica, Inc. See LICENSE for details.