Migrate away from Yarn 1 (Classic) as package manager

[MikeMcC399]

Feature

Migrate away from Yarn Classic v1 as package manager. This could be to Yarn Modern v4 or to npm.

Reason

Yarn 1 (Classic) is stated to be frozen. The Yarn 1 GitHub repo contains the "About" text:

The 1.x line is frozen - features and bugfixes now happen on https://github.com/yarnpkg/berry"

The cypress-io/cypress-realworld-app should be based on current and supported technologies in order to provide a useful example of Cypress in practice.

[jennifer-shehane]

Welcome to any PRs to update this

[MikeMcC399]

@jennifer-shehane

Related issues that @astone123 raised are:

• Migrate to MUI v5 #1418
• Migrate away from react-infinite-calendar #1419
• Migrate away from express-graphql package #1420

See also

• Installation warnings Rev3 #1508

It may be difficult to migrate before these issues are addressed.

[MikeMcC399]

npm

• Attempting to migrate from Yarn Classic to npm hits multiple fatal dependency issues running npm install. Needs resolution of Migrate away from react-infinite-calendar #1419

Yarn Modern

• After migrating from Yarn Classic to Yarn Modern (4.1.0) executing yarn dev crashes with

[start:api:watch] Error: Cannot find module '../src/aws-exports'
[start:api:watch] [nodemon] app crashed - waiting for file changes before starting...

[MikeMcC399]

Yarn Modern

I revisited this and it seems that the issues were caused by the hierarchy of lifecycle scripts not executing as expected. The following set of commands, with a workaround, does however allow both E2E and Component Testing to work under Yarn 4.5.0:

yarn set version stable
yarn
yarn copy:mock:awsexports && yarn copy:mock:awsexportses5 # workaround for lifecycle script issues
yarn dev

Wait until message "Backend server running at http://localhost:3001" appears, then execute in a separate terminal:

yarn cypress:run
yarn cypress:run:component