Pipes

Pipes implemented on top of pipelines. Pipes run on method arguments and can transform argument value Pipe must implement the IPipe interface.

if the pipe decorate a class it will run on all class methods.

if pipe decorate a method it will run on the first argument

Usage

Transform

import {pipe,IPip} from '@appolo/engine';

import {define} from '@appolo/inject';

@define()

export class DatePipe implements IPipe{

async transform(value:number,context:PipelineContext){

return new Date(value);

}

}

export const date = ()=> pipe(DatePipe);

now lets use out date pipe

@define()

export class SomeClass {

@date()

test(value:Date|number){

return value;

}

}

injector.get(SomeClass).test(1604047612) instanceof Date //true

Validate

we can validate the argument and throw error

import {pipe,IPip} from '@appolo/engine';

import {define} from '@appolo/inject';

import { ObjectSchema } from '@hapi/joi';

@define()

export class ValidatePipe implements IPipeline{

async transform(value:number,context:PipelineContext<{schema:ObjectSchema}>){

const { error } = context.metadata.schema.validate(value);

if (error) {

throw new BadRequestException('Validation failed');

}

return value;

}

}

export const validate = (schema:ObjectSchema)=> pipe(ValidatePipe,{schema})

@define()

export class SomeClass {

@validate(joi.object().keys({a:joi.string()}))

test(params:{a:string}){

return params;

}

}

injector.get(SomeClass).test({a:11}) //throws BadRequestException