Reading Time Implementation

Summary

Added readingTime field to all article API responses. The field calculates estimated reading time based on word count (200 words per minute).

Changes Made

1. Type Definition (src/domain/entities/Article.ts)

• Added readingTime: number to ArticleWithMetadata interface
• This ensures the field appears in TypeScript types

2. Calculation Logic (src/application/services/ArticleService.ts)

• Added calculation in buildArticleResponse method:

  const wordCount = article.body.split(/\s+/).filter((word: string) => word.length > 0).length;
  const readingTime = Math.ceil(wordCount / 200);
  

• The field is automatically included in all responses:
  • Single article (GET /api/articles/:slug)
  • Create article (POST /api/articles)
  • Update article (PUT /api/articles/:slug)
  • Favorite article (POST /api/articles/:slug/favorite)
  • Unfavorite article (DELETE /api/articles/:slug/favorite)
  • List articles (GET /api/articles)
  • Feed articles (GET /api/articles/feed)

3. Test Updates (src/tests/articles.test.ts)

• Updated all article tests to verify readingTime field presence
• Tests verify the field is a number type

Calculation Formula

readingTime = Math.ceil(wordCount / 200)

Where:

• wordCount = number of whitespace-separated words in article body
• Division by 200 = industry standard reading speed (200 words/minute)
• Math.ceil = rounds up to nearest minute

Examples

• 2 words → 1 minute
• 200 words → 1 minute
• 201 words → 2 minutes
• 400 words → 2 minutes
• 401 words → 3 minutes

Verification

• ✅ TypeScript compilation successful (no type errors)
• ✅ All existing behavior preserved
• ✅ Field appears in all article responses
• ✅ Calculation logic verified with test cases