Issue description

Selecting BLOB/Buffer columns fails in TypeORM 0.3.26 with TypeError: val.toString is not a function (regression from 0.3.25)

Expected Behavior

• Queries that select BLOB/Buffer columns (e.g., mediumblob) should return Node.js Buffer instances, just as in 0.3.25.
• Binary data should be retrievable via getOne(), getRawOne(), or repository.findOne({ select: ['image'] }) without throwing errors.

Actual Behavior

• Any attempt to select a BLOB column results in TypeError: val.toString is not a function originating from sqlstring.
• The query never executes; no results are returned.

Steps to reproduce

Create a simple entity with a blob column:

@Entity()
export class Person {
  @PrimaryGeneratedColumn('uuid')
  id: string;

  @Column('mediumblob', { select: false, nullable: true })
  image: Buffer;
}

Run a query that selects the blob field:

const person = await repository
  .createQueryBuilder('person')
  .addSelect('person.image')
  .where('person.id = :id', { id })
  .getOne();

Observe the error:

TypeError: val.toString is not a function

My Environment

Additional Context

After upgrading to TypeORM 0.3.26, queries involving BLOB/Buffer columns fail with:

TypeError: val.toString is not a function
    at Object.escape (.../node_modules/sqlstring/lib/SqlString.js:52:33)
    at Object.format (.../node_modules/sqlstring/lib/SqlString.js:100:19)
    at PoolConnection.format (.../node_modules/mysql2/lib/base/connection.js:521:22)
    at PoolConnection.query (.../node_modules/mysql2/lib/base/connection.js:566:25)
    ...

This did not happen with TypeORM 0.3.25. The error appears to be related to the change in 0.3.26 where stringifyObjects: true is now passed to the MySQL driver by default.

PR 11574 seems to introduce the issue. I am not sure if this behavior is intended this way, because it seems like it is a breaking change.

To fix it I had to change my connection settings as stated in the PR:

it can be disabled by passing stringifyObjects: false in the extra connection options if needed.
This seems to work for me.

Relevant Database Driver(s)

• aurora-mysql
• aurora-postgres
• better-sqlite3
• cockroachdb
• cordova
• expo
• mongodb
• mysql
• nativescript
• oracle
• postgres
• react-native
• sap
• spanner
• sqlite
• sqlite-abstract
• sqljs
• sqlserver

Are you willing to resolve this issue by submitting a Pull Request?

No, I don’t have the time and I’m okay to wait for the community / maintainers to resolve this issue.