Argument Pipe

In actual development, we rarely use local and global pipes. Instead, we use argument pipes

Create Argument Pipe

Argument pipe do not exist independently; they are created based on local pipe. The following uses the local pipe number as an example to demonstrate how to create an argument pipe

+ import { createArgumentPipe, Pipe } from 'vona-module-a-aspect';

@Pipe()
class PipeNumber {
  async transform(value: TypePipeNumberData) {
    const valueNew = Number(value);
    if (Number.isNaN(valueNew)) this.app.throw(400);
    return valueNew;
  }
}

+ export const ArgNumber = createArgumentPipe('demo-student:number');

• createArgumentPipe: Pass in the local pipe name and create the argument pipe decorator

Using Argument Pipe

Use the argument pipe directly on the method parameters

class ControllerStudent {
  @Web.get(':id')
+ async findOne(@ArgNumber() @Arg.param('id') id: any) {}
}

• @Arg.param: Built-in argument pipe
• Argument pipes order: @Arg.param > @ArgNumber

Specifying Parameters When Using

You can specify pipe parameters when using pipes

class ControllerStudent {
  @Web.get(':id')
- async findOne(@ArgNumber() @Arg.param('id') id: any) {}
+ async findOne(@ArgNumber({ errorCode: 500 }) @Arg.param('id') id: any) {}
}

INFO

Why use id: any?

This is to demonstrate the use of the argument pipe. If you use id: number, you already have the ability to validate number-type parameters, eliminating the need to use @ArgNumber()