Cypress load environment variables in custom commands

Question

I'm building a Next.js app and write my tests using Cypress. I configure the environment variables using a .env.local file locally. In the CI pipeline, they are defined normally.

I'm trying to write a custom command in Cypress that encrypts a session in cypress/support/command.ts.

import { encryptSession } from 'utils/sessions';

Cypress.Commands.add(
  'loginWithCookie',
  ({
    issuer = 'some-issuer',
    publicAddress = 'some-address',
    email = 'some-mail',
  } = {}) => {
    const session = { issuer, publicAddress, email };

    return encryptSession(session).then(token => {
      cy.setCookie('my-session-token', token);
      return session;
    });
  },
);

When this command runs, it fails because encryptSession uses a TOKEN_SECRET environment variable, that Cypress doesn't load.

import Iron from '@hapi/iron';

const TOKEN_SECRET = process.env.TOKEN_SECRET || '';

export function encryptSession(session: Record<string, unknown>) {
  return Iron.seal(session, TOKEN_SECRET, Iron.defaults);
}

How can I get Cypress to load the environment variables from that file, if its there (= only locally because the variables are defined in the CI - it should detect the other variables in the pipeline normally, so the equivalent of detecting a variable that has been set with export MY_VAR=foo)?

Answer 1

Steve's answer actually helped me to end up with this code in cypress/plugins/index.ts.

import dotenv from 'dotenv';

dotenv.config({ path: '.env.local' });

import { encryptSession } from 'utils/sessions';

/**
 * @type {Cypress.PluginConfig}
 */
const pluginConfig: Cypress.PluginConfig = (on, config) => {
  on('task', {
    encryptSession: (session: {
      issuer: string;
      publicAddress: string;
      email: string;
    }) => encryptSession(session),
  });
};

export default pluginConfig;

Then in cypress/support/commands.ts.

Cypress.Commands.add(
  'loginWithCookie',
  ({
    issuer = 'some-issuer',
    publicAddress = 'some-address',
    email = 'some-email',
  } = {}) => {
    const session = { issuer, publicAddress, email };

    return cy.task<string>('encryptSession', session).then(token => {
      return cy.setCookie('my-secret-token', token).then(() => {
        return session;
      });
    });
  },
);