feat!: bundle only real defaults in app config

[arbrandes]

Description

Every key an app declares in its own config is a key commonAppConfig can never supply, since app config is the highest-precedence layer. Catalog declared ten, so values an operator set platform-wide through MFE_CONFIG silently lost to bundled defaults. Only HOMEPAGE_COURSE_MAX: 9 is a real default, so it moves to App.defaultConfig (frontend-base ADR 0017, added by openedx/frontend-base#298), which resolves below commonAppConfig; the other nine were no-ops against already-guarded reads or empty-string placeholders that now live at the point of use.

LEARNING_BASE_URL is required config with no default that can work, so getLearningHomePageUrl returns null when it is unset and the course-about "View course" buttons are gated on a resolved URL. An operator who never set it now gets no button rather than one pointing at catalog's own origin.

The peer dependency moves to @openedx/frontend-base 2.0.0-alpha.4, the first release carrying App.defaultConfig. Lint, tsc, build, and all 387 tests pass against it. The second commit is a mechanical lint:fix for a rule frontend-base 2.0 enables.

LLM usage notice

Built with assistance from Claude.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.55%. Comparing base (b8834b5) to head (1212202).

Additional details and impacted files

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##           master     #156   +/-   ##
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  Coverage   99.54%   99.55%           
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  Files         100      100           
  Lines         666      671    +5     
  Branches      167      168    +1     
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+ Hits          663      668    +5     
  Misses          2        2           
  Partials        1        1           

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[brian-smith-tcril]

Looks great!

One non-blocking nit for consistency (inline comment written by claude) in how we're getting strings out of the config.

I specifically flagged not loving the "cast to string | undefined" pattern to claude and the result of the conversation is in that inline comment.

[brian-smith-tcril]

Nit / readability — this is behavior-preserving and the cast is doing the right thing now that the key can actually be absent.

Dropping the bundled defaults turns "read a string out of app config" into a recurring shape. It shows up as a cast in four places:

• src/catalog/CatalogPage.tsx:85
• src/course-about/CourseAboutPage.tsx:41
• src/home/components/courses-list/CoursesList.tsx:66
• src/course-about/course-sidebar/sidebar-social/utils.ts:29 (COURSE_ABOUT_TWITTER_ACCOUNT)

...and a fifth time as a hand-written narrow in getLearningHomePageUrl:

const learningBaseUrl = getAppConfig(appId).LEARNING_BASE_URL;
return typeof learningBaseUrl === 'string' && learningBaseUrl
  ? `${learningBaseUrl}/course/${courseId}/home`
  : null;

One accessor would cover all five:

// src/config.ts
import { getAppConfig } from '@openedx/frontend-base';
import { appId } from '@src/constants';

export const getStringConfig = (key: string, fallback = ''): string => {
  const value = getAppConfig(appId)[key];
  return typeof value === 'string' ? value : fallback;
};

The cast sites lose the cast and the parens:

supportEmail: getStringConfig('INFO_EMAIL'),

and getLearningHomePageUrl keeps its null-when-unset contract without restating the narrow, since the '' fallback is falsy:

const learningBaseUrl = getStringConfig('LEARNING_BASE_URL');
return learningBaseUrl ? `${learningBaseUrl}/course/${courseId}/home` : null;

Behavior is identical at all five sites either way — it's just one implementation of "string or fall back" instead of two spellings of it.

Entirely reasonable to skip if you'd rather not add an indirection for this.

[arbrandes]

Actually, I love it. Thanks!

[openedx-semantic-release-bot]

🎉 This PR is included in version 1.0.0-alpha.2 🎉

The release is available on:

• npm package (@alpha dist-tag)
• GitHub release

Your semantic-release bot 📦🚀