A rudimentary Cypress plugin(?) for automatically restarting tests after Webpack Hot Module Replacement (HMR) updates.
npm install --save-dev cypress-hmr-restarter
// E.g. in cypress/support/index.js
// For webpack HMR (used in e.g. create-react-app or angular 11+)
import 'cypress-hmr-restarter';
// For webpack-hot-middleware (used in e.g. gatsby)
import 'cypress-hmr-restarter/gatsby';
baseUrl
or hmrUrl
is configured// E.g. in cypress.json
{
// Works with e.g. default create-react-app configuration
"baseUrl": "http://localhost:3000"
}
{
// Overriding then URL used to connect, otherwise created from the baseUrl
"hmrUrl": "ws://localhost:3000/sockjs-node", // Default import
"hmrUrl": "ws://localhost:3000/websocket", // Angular 11+ import
"hmrUrl": "http://localhost:3000/__webpack_hmr", // Gatsby import
// Overrides delay between event and restart (ms)
"hmrRestartDelay": 1500
}
When using the Cypress Test Runner (cypress open
), after the window has loaded, it will try to connect and listen for events. When an event signifying a change has happened, it will first try clicking the stop button, and then, after a short delay, it will click the restart button.
The default import connects to the webpack-dev-server
websocket at either <hmrUrl>
or ws://<baseUrl>/sockjs-node
(wss:
if https:
), and listens for messages with the type invalid
.
IMPORTANT: You need to ensure that transportMode
option of webpack-dev-server
is set to ws
for the feature to work.
The gatsby import connects to the webpack-hot-middleware
event source at either <hmrUrl>
or <baseUrl>/__webpack_hmr
, and listens for messages with the action built
.