Updating JSON using QueryBuilder

Question

I am creating a project using nestjs and postgress. I want to update a property (owner) in my table orders. So the property is a JSON object which is similar to this { name: "John", gender: "M" } and would like to update it to { name: "Jacob", gender: "M" }

My current function is this, but its seems to be not working

return this.createQueryBuilder('orders')
      .update()
      .set({'owner->>firstName': newFirstName} as any)
      .where(`id = :id`, { id: id})

PS: I cannot use jsonb as we are using old version of postgres and typeorm