Bug: Partial i18n overrides with language: 'fr' cause fallback to English, despite loading login_fr.json

[sankarsan20]

Describe the bug

When configuring the Okta Sign-In Widget with language: 'fr' and a partial override in i18n.fr, the widget successfully loads the built-in login_fr.json French translation file from the network — but still falls back to English for all untranslated keys in the UI.

This suggests that supplying i18n.fr causes the widget to ignore or bypass the loaded login_fr.json translations, treating the provided keys as a complete replacement, not an override.

Reproduction Steps

1. Set the language option to 'fr'.

2. Provide a partial i18n override like:

i18n: {
  fr: {
    'primaryauth.title': 'Connexion personnalisée'
  }
}

3. Load the widget and observe the UI.

SDK Versions

System:
OS: Windows 11 10.0.26100
CPU: (8) x64 11th Gen Intel(R) Core(TM) i7-1185G7 @ 3.00GHz
Memory: 11.28 GB / 31.71 GB
Binaries:
Node: 24.3.0 - C:\nvm4w\nodejs\node.EXE
Yarn: 3.6.4 - C:\nvm4w\nodejs\yarn.CMD
npm: 11.4.2 - C:\nvm4w\nodejs\npm.CMD
Browsers:
Edge: Chromium (138.0.3351.55)
Internet Explorer: 11.0.26100.1882
npmPackages:
@okta/okta-auth-js: ^7.3.1 => 7.12.1
@okta/okta-signin-widget: ^6.9.0 => 6.9.0

Additional Information

Expected Behavior

• The widget should use the translations from login_fr.json for all untranslated keys.

• Custom values in i18n.fr should override corresponding keys from the built-in French translations only.

• The UI should remain fully in French, except for overridden text.

** Actual Behavior**

• login_fr.json is loaded via network.

• However, only keys in the provided i18n.fr object are used.

• All other keys fall back to English, not to the built-in French from login_fr.json.

[Drgeeda]

Is this a tag or bug

[sankarsan20]

Hello @Drgeeda
It's a bug.