typeorm-stubs

Stubs generator for Typeorm entities. It uses typeorm metadata to get the type of the column and generate a random value.

Contents

• Usage
  • Simple usage
  • Deep generation
  • Null defaults
  • Generator overriding
• Todos

Usage

Simple usage

You may generate a single stub or an array of stubs from Typeorm entity like this:

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

  @CreateDateColumn()
  public createdAt: Date;
  
  @Column({ type: 'varchar', nullable: false })
  public name: string;
  
  @Column({ type: 'integer', nullable: false })
  public index: number;
  
  @Column({ type: 'boolean', nullable: false })
  public isMain: boolean;
}

This code generates a single stub:

const stub = new Stub().createOne(MyEntity);

It gives you an object like this:

const stub: MyEntity = {
  id: '125a1c28-2938-4996-95f0-d768cbc3c15e',
  createdAt: new Date('2022-10-09T04:43:05.976Z'),
  name: 'Proin interdum adipiscing vel tortor.',
  index: 487,
  isMain: true,
}

For an array of stubs use this code:

const stubs = new Stub().createMany(MyEntity, 5);

It gives you 5 stubs in array. Param count is optional and can be omitted, then random count of stubs will be generated.

Deep generation

You may create a stub from entity with relations, e.g.:

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

  @CreateDateColumn()
  public createdAt: Date;
  
  @Column({ type: 'varchar', nullable: false })
  public name: string;
  
  @Column({ type: 'integer', nullable: false })
  public index: number;
  
  @Column({ type: 'boolean', nullable: false })
  public isMain: boolean;
  
  @Column({ type: 'uuid', nullable: true })
  public relationId?: string;
  
  @ManyToOne(() => RelationEntity)
  @JoinColumn({ name: 'relationId' })
  public relation?: RelationEntity;
}

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

  @CreateDateColumn()
  public createdAt: Date;
  
  @Column({ type: 'varchar', nullable: false })
  public description: string;
  
  @OneToMany(() => DeepRelation)
  public deepRelations: DeepRelation[];
}

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

  @CreateDateColumn()
  public createdAt: Date;

  @Column({ type: 'integer', nullable: false })
  public index: number;

  @Column({ type: 'uuid', nullable: true })
  public parentId?: string;

  @ManyToOne(() => RelationEntity)
  @JoinColumn({ name: 'relationId' })
  public parent?: RelationEntity;
}

It gives:

const stub: MyEntity = {
  id: '125a1c28-2938-4996-95f0-d768cbc3c15e',
  createdAt: new Date('2022-10-09T04:43:05.976Z'),
  name: 'Proin interdum adipiscing vel tortor.',
  index: 487,
  isMain: true,
  relationId: '3631150a-c6be-4fab-9896-182e67056efe',
  relation: {
    id: '3631150a-c6be-4fab-9896-182e67056efe',
    createdAt: new Date('2022-10-09T04:43:05.976Z'),
    description: 'Sit ut, mattis cursus. porttitor feugiat sit malesuada vitae.',
    deepRelations: [
      {
        id: '7d8b2f6b-bd52-424a-adcf-770a979690d1',
        createdAt: new Date('2022-10-09T04:43:05.976Z'),
        index: 15,
        parentId: '3631150a-c6be-4fab-9896-182e67056efe',
      },
      {
        id: '02abe928-08e5-412a-957b-7a45382df9fc',
        createdAt: new Date('2022-10-09T04:43:05.976Z'),
        index: 8,
        parentId: '3631150a-c6be-4fab-9896-182e67056efe',
      },
      {
        id: '74a1ded5-e9d9-4fd4-bb1e-161d4d0df412',
        createdAt: new Date('2022-10-09T04:43:05.976Z'),
        index: 593,
        parentId: '3631150a-c6be-4fab-9896-182e67056efe',
      },
      {
        id: '8baa6530-3fa3-4778-ba11-f675d7d653a4',
        createdAt: new Date('2022-10-09T04:43:05.976Z'),
        index: 967,
        parentId: '3631150a-c6be-4fab-9896-182e67056efe',
      },
    ],
  },
}

Foreign keys will be mapped to an entity if it's possible.

Note that circular dependencies will be omitted, and entities won't be generated twice.

A large number of elements in the array makes the generation slower. To improve performance you can pass deep: false in the options, this will disable all deep generation for stubs, e.g.:

const stub = new Stub().createMany(MyEntity, 536, {
  deep: false,
});

Null defaults

By passing nullDefaults: true in the options, the stub will return null for any column that is flagged as nullable, e.g. given the entity:

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

  @CreateDateColumn()
  public createdAt: Date;
  
  @Column({ type: 'varchar', nullable: false })
  public name: string;
  
  @Column({ type: 'integer', nullable: true })
  public index: number;
  
  @Column({ type: 'boolean', nullable: true })
  public isMain: boolean;
  
}

Then calling:

const stubs = new Stub().createOne(MyEntity, { nullDefaults: true });

Will give:

const stub: MyEntity = {
  id: '125a1c28-2938-4996-95f0-d768cbc3c15e',
  createdAt: new Date('2022-10-09T04:43:05.976Z'),
  name: 'Proin interdum adipiscing vel tortor.',
  index: null,
  isMain: null
}

Generator overriding

You may override a stub generator for specific types, e.g. for string. You should create a new class implementing StubGenerator interface and pass it to Stub:

class MyGenerator implements StubGenerator {
  public generateString(_column: ColumnMetadataArgs): string {
    return 'overrided!';
  }
}

const stub = new Stub(MyGenerator).createOne(MyEntity);

It gives:

const stub: MyEntity = {
  id: '125a1c28-2938-4996-95f0-d768cbc3c15e',
  createdAt: new Date('2022-10-09T04:43:05.976Z'),
  name: 'overrided!',
  index: 487,
  isMain: true,
}

Todos

• "level" option for deep generation
• Tests
• Overriding by column type
• Generating PostgreSQL arrays, JSONs