question: decorator information missing from shared project

[zelid]

I have a need to use the same decorated input class like:

export class CreateLoginInput {

    @Length(2, 20)
    name: string

    @IsEmail()
    email: string
}

class-validator works fine when decorated class and validation action are in the same project.

When used in a shared project config like: client-app, server-app, shared-lib where CreateLoginInput is placed in a shared lib and validation is done in both client and server app it stops to work and validation always returns no errors.

server-app and client-app are separate projects with very different set of node_modules and can't be placed inside one project. I moved CreateLoginInput class to shared-lib project to make other projects consume input validation.

When CreateLoginInput is included from shared-lib validation stops to work, probably the decorator metadata is missed.

How to configure class-validator to make validation work when classes are included from a shared project?

[MichalLytek]

Looks like related to #132.
@NoNameProvided what's your solution now, when the folder can't be placed inside one project?

[NoNameProvided]

@zelid Do you import your shared-lib from node_modules?

[NoNameProvided]

Hey @zelid!

I just gave a look and it works for me. There are 3 things you miss probably.

No metadata is emitted

You need to build your shared project, and you need to build it with the right settings. (Technically you don't need to, but you should.) Your shared-libs tsconfig.json must contain these lines.

"experimentalDecorators": true,
"emitDecoratorMetadata": true,
"declaration": true  

(Technically declaration is not needed but without it, you won't have code-completion.)

Shared classes must be imported

You must import your shared classes at least once at the beginning of your project. Otherwise, the decorator metadata is not recorded.

You can do it easily by re-exporting everything in the root of your shared-lib and then import everything in your main-projects via

import * as VALIDATOR_CLASSES from 'shared-lib';

You must validate an instance of the class.

class-validator decide what decorators to run based on instanceof so you actually need to pass in an instance of the class, not just a simple object.

import { validateSync } from 'class-validator';
import { CreateLoginInput } from 'shared-lib';

const instance = new CreateLoginInput();
const plainObject = {};

console.log(validateSync(instance)); // returns the ValidationError[] array.
console.log(validateSync(plainObject)); // returns empty array by deault
// second call can return an error if you set `forbidUnknownValues` to true.

---

I have created an example, my folder structure is:

.
|____node_modules
| |____validator
| | |____validator.js
| | |____ (lot of other files here)
| |____shared-lib
| | |____create-login.payload.ts
| | |____index.js
| | |____create-login.payload.d.ts
| | |____package.json
| | |____create-login.payload.js
| | |____tsconfig.json
| | |____index.ts
| | |____index.d.ts
| |____ansicolor
| | |____ansicolor.js
| | |____ (lot of other files here)
| |____class-validator
| | |____ (lot of other files here)
|____index.js
|____package-lock.json
|____package.json
|____tsconfig.json
|____index.ts

Where my /index.ts file looks like this:

import { validateSync } from 'class-validator';
import { CreateLoginInput } from 'shared-lib';

const instance = new CreateLoginInput();


console.log(validateSync(instance));

And node_modules/shared-lib/create-login.payload.ts looks like this:

import { Length, IsEmail } from 'class-validator';

export class CreateLoginInput {

  @Length(2, 20)
  public name!: string

  @IsEmail()
  public email!: string
}

I attach the complete example as an attachment: class-validator-181.zip

Please let me know if this solved your issue.

[zelid]

@NoNameProvided thanks for detailed explanation!

shared-lib is a separate project under node_modules because it is the last approach I tried to manage local packages using lerna.

@NoNameProvided how do you manage your shared library code, do you put it as separate private/local npm package or shared folder through relative/symlinked paths?

The issue with my code was indeed with the shared-lib
tsconfig.json had no "declaration": true and had main script from package.json pointing to ./src/index.ts instead of ./dist/indiex.js

The second approach I've tired is including shared-lib file directly from filesystem through a relative path include { CreateLoginInput } from '../../../../../local-pakcages/shared-lib/src' and in this case decorators metadata was also not available and I did not manage how to get it work.

Local private shared-lib works fine when when used as a separate correctly built npm package.

[NoNameProvided]

We use private npm packages.

I will go ahead and close this as solved, let me know if you have any other quetstion.

[shusson]

Just a heads up to anyone who encounters something like this, definitely look into #132 which was causing our issues. Specifically this comment #132 (comment) which explains the issue quite clearly.