Seeding Data

Seeds put initial data - roles, permissions, lookup tables, test users - into a relational database. In NodeC, seeds are TypeORM migrations that live in a separate folder, so they run with migration:run, in order with the schema migrations, on every environment.

1. Create the seed file

src/data/<dataModule>/seeds/common/<timestamp>-<Name>.ts

import { MigrationInterface, QueryRunner } from 'typeorm';

export class TaskStatuses1780000000001 implements MigrationInterface {
  name = 'TaskStatuses1780000000001';

  public async up(queryRunner: QueryRunner): Promise<void> {
    await queryRunner.query(
      "INSERT INTO `taskStatuses` (`id`, `name`) VALUES (1, 'open'), (2, 'done');"
    );
  }

  public async down(_queryRunner: QueryRunner): Promise<void> {}
}

The class name must end with the timestamp, and name must match it - TypeORM uses them to track which migrations have run.

WARNING

Use a timestamp later than the migrations the seed depends on. Seeds and migrations run together, ordered by timestamp, so a seed with an older timestamp runs before the table it inserts into exists.

WARNING

Read the later migrations before writing SQL - tables and columns get renamed over time (e.g. the reference app's authorizationPoints became permissions).

2. Rebuild and run

The generated datasource file loads migrations and seeds from dist, so build first:

npm run build
DATASOURCE_ENV=local npm run generate:datasource-files   # only needed once per environment
npx typeorm migration:run -d datasource-db-local.js

TIP

JSON columns are inserted as strings, so escape backslashes twice in regular expressions inside them: \\\\. in the TypeScript source becomes \. in the stored JSON.

The reference app's seeds are in apps/test/src/data/db/seeds/common - the initial data, categories and the permission data the e2e tests rely on.

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