nbook-api/src/transformers/array.transformer.ts

import { ValueTransformer } from 'typeorm'

export class ArrayTransformer implements ValueTransformer {
    to(value: string[]): string {
        return value?.join()
    }
    from(value: string): string[] {
        if (value) {
            return value.split(',')
        }
        return []
    }
}