How to set the browser's language in Cypress.io (electron/chrome)?

Question

My question is about configuring Cypress to launch a browser instance in a certain language.

In order to:

• make assertions on localized (i18n) text labels?
• check i18n features (switching between languages)
• bypass issues of Continuous Integration (CI/CD) when, for example, on a local computer, the browser default to fr_FR, and on the CI/CD VM it defaults to en_US?

I tried (without much success):

• using LANGUAGE=en_US from the terminal invocation,
• using the Browser's API plugin (see Cypress' browser launch API documentation)

Thanks!

Answer 1

navigator has two lang props:

• language ({ value: 'en-GB'}
• languages(['en-GB'])

navigator.language refers to the first element of navigator.languages but some libraries check navigator.languages[0] instead of navigator.language, so better if you set both properties

onBeforeLoad: (window, ...args) => {
  Object.defineProperty(window.navigator, 'language', { value: 'en-GB' });
  Object.defineProperty(window.navigator, 'languages', ['en-GB']);

ref: https://developer.mozilla.org/en-US/docs/Web/API/NavigatorLanguage/languages