ClassSerializerInterceptor: .classToPlain is not a function

[c43721]

For those looking for a quick fix,

Downgrade to class-transformer: 0.4.0:

• npm install class-transformer@0.4.0
• yarn add class-transformer@0.4.0

Is there an existing issue for this?

• I have searched the existing issues

Current behavior

When a controller uses ClassSerializerInterceptor, it will throw a TypeError: classTransformer.classToPlain is not a function due to a breaking change in the latest release https://github.com/typestack/class-transformer/blob/develop/CHANGELOG.md

Minimum reproduction code

https://github.com/nestjs/nest/tree/master/sample/21-serializer

Steps to reproduce

1. Copy the Serializer example from Nestjs
2. Run the application
3. Make a request to a controller, see error.

Expected behavior

To serialize the data correctly.

Package

• I don't know. Or some 3rd-party package
• @nestjs/common
• @nestjs/core
• @nestjs/microservices
• @nestjs/platform-express
• @nestjs/platform-fastify
• @nestjs/platform-socket.io
• @nestjs/platform-ws
• @nestjs/testing
• @nestjs/websockets
• Other (see below)

Other package

class-serializer

NestJS version

8.2.2

Packages versions

"@nestjs/common": "^8.2.2"
"@nestjs/core": "^8.2.2"
"class-transformer": "^0.5.0"
"class-validator": "^0.13.2"

Node.js version

v16.6.1

In which operating systems have you tested?

• macOS
• Windows
• Linux

Other

The changes in class-validator have fixed the security vulnerabilities and have changed the names of the functions used. This should be patched asap, as this would benefit those who are not using the nestjs/class-transformer.

[ahmedsaptan]

I have the same issue, when I try to add any validation I get this error.

[jmcdo29]

Downgrade to less than 0.5.0 for class-transformer. In your package.json you should be able to do "class-transformer": "<=0.4.0" as 0.4.1 was an accidental patch release for a major change

[ahmedsaptan]

thank you, it working now.

[Lobaton2020]

Thank you guys

[kamilmysliwiec]

Let's track this here #8638