Nestjs Injectable class transformer

Community libarary that allows you to use DI to transform your dto.

Table of Contents

- How to use
- Not Supported

---

How to use

Installation

``shell
$ npm install nestjs-class-transformer
`



Using yarn

`shell
$ yarn add nestjs-class-transformer
`







Using pnpm

`shell
$ pnpm install nestjs-class-transformer
`



Usage

First add the intercepter to the controller

`typescript
import { TransformerInterceptor } from "nestjs-class-transformer";

@UseInterceptors(TransformerInterceptor)
export class SomeController {}
`

> Remeber, you need to use UseInterceptors on every controller you need it's value to be transformed.
> You CANNOT use useGlobalInterceptors because each controller must include his own interceptor to be able to use DI correctly.

Then you need to define a transformer.

A transformer is just an injectable class that has a transform as shown below.
This class can inject whatever it needs and is accessible in it's module.

`typescript
import { Transform } from "nestjs-class-transformer";

export class NameTransformer implements Transform {
constructor(public injectedService: InjectedService) {}

transform(params: TransformFnParams) {
return injectedService.formatName(params.value, params.key);
}
}
`

Last, in your dto class do the following:

`typescript
import { Transformer } from "nestjs-class-transformer";
class SomeDto {
@Transformer(NameTransformer)
name: string;
}
``

And that is it, congratulations now you can transform your dtos from your injectable services with ease.

Not Supported

- it does not work for incoming dto, it only transforms outgoing dto.
- it does not support any of the TransformOptions object.