How to add index to many-to-many relationship in TypeORM

Question

When I add a many-to-many relationship in typeORM entities, how can I add index to the relation columns?

@Entity()
export class Tag {
  @Column()
  id: number

  //@Index() does not work here...
  @ManyToMany(() => Todo, (todo) => todo.tags)
  todos: Todo[];

......

Answer 1

Turns out the indices are add automatically. Then I have to ask how can I tell typeORM not to add the index since it may not be needed.....