prisma-loader

prisma-loader

prisma-loader is a utility to load your database with initial data (a.k.a «fixture»). You specify the initial data in a YAML file. Use it to get your database into a predictable state in your CI/CD pipeline or before every test run during testing.

What is Prisma?

Prisma is an open-source database toolkit, that replaces traditional ORMs and makes database access easy with an auto-generated query builder for TypeScript & Node.js.

👉 prisma.io/docs/

Usage from the Command Line

yarn add prisma-loader -D
npx prisma-loader path/to/data.yml [more.yml files.yml]

Let's suppose we want to load two users into our database. Let's also assume, that our Prisma Schema has a type «user» already defined (see example schema.prisma).

# initial-data.yml
user:
  - name: Admin
    email: [e-mail]
    password: test
    role: ADMIN
  - name: Student
    email: [e-mail]
    password: test
    role: STUDENT

This will generate two users in our database. You can define further types and initial data within the same YAML file:

# initial-data.yml
user:
  - name: Admin
    ...

school:
  - name: School One
    ...

If your database already contains data, e.g. from a previous initialization run, then you may want to first delete this data. You can do this by specifying which types to delete in the YAML file:

# initial-data.yml
delete:
  - user
  - school
  - ...

user:
  - name: Admin
    ...

school:
  - name: School One
    ...

Watch out, depending on how the data types reference each other you may run into problems when deleting data, as Prisma does not yet support cascading deletes (see this issue). List those types first, which no other types references to as a required relation.

Usage in your code

You can also use this tool from within your code, e.g. to load data before every test run

import { loadFixture } from "prisma-loader";

loadFixture("examples/example.yml");

This will execute the data load specified in the YAML file.

Usage in Cypress

If you would like to use this to load predefined data before every test run with cypress.io, then you need to set up cypress as follows:

// in cypress/plugins/index.js
const { loadFixture } = require("prisma-loader");

module.exports = (on, config) => {
  on("task", {
    async prismaLoader(fixtureFile) {
      const file = `${config.fixturesFolder}/${fixtureFile}`;
      await loadFixture(file);
      return null;
    },
  });
}

This makes available a cypress task, which can be used as follows:

describe("Some test", () => {
  beforeEach(() => {
    // test-data.yml will be loaded from cypress/fixtures/...
    cy.task("prismaLoader", "test-data.yml");
  });

  it("Already has the data loaded", {
    ...
  });