Support array of ValueTransformer in column options

[Samox]

Issue type:

[ ] question
[ ] bug report
[x] feature request
[ ] documentation issue

Database system/driver:

[ ] cordova
[ ] mongodb
[ ] mssql
[ ] mysql / mariadb
[ ] oracle
[x] postgres
[ ] cockroachdb
[ ] sqlite
[ ] sqljs
[ ] react-native
[ ] expo

TypeORM version:

[ ] latest
[ ] @next
[x] ^0.2.14 (or put your version here)

Steps to reproduce or a small repository showing the problem:

Hi, I'd like to be able to apply multiple ValueTransformers to a field:

import { ValueTransformer } from "typeorm";

export const lowercase: ValueTransformer = {
    to: (entityValue: string) => { return entityValue.toLocaleLowerCase() },
    from: (databaseValue: string) => { return databaseValue }
}

export const encrypt: ValueTransformer = {
    to: (entityValue: string) => { return crypto.encrypt(entityValue) },
    from: (databaseValue: string) => { return crypto.decrypt(databaseValue) }
}

And use them like this:

  @Column({ unique: true, transformer: [lowercase, encrypt] })
  email: string;

Is it on the road map ?
I'd be more than happy to do a PR if this sounds a good idea to you !😇

Thanks

[Samox]

I made a POC for Postgres and 2 value transformers #4009