feat: add string utility function to truncate text

[danielvo594520]

提案の概要

長いテキストを指定した長さで切り詰めるユーティリティ関数を追加してください。

背景 / 課題

• lib/utils/string.ts に truncate 関数を作成
• 引数: text: string, maxLength: number, suffix?: string (デフォルト: "...")
• 戻り値: 切り詰めたテキスト
• テストファイル lib/utils/test.ts も作成

解決策のイメージ

例

truncate("Hello World", 5) // => "Hello..."
truncate("Hi", 10) // => "Hi"
truncate("Hello World", 5, "…") // => "Hello…"

## 代替案の検討

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## 関連情報

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[claude]

Claude finished @danielvo594520's task in 2m 49s —— View job • claude/issue-46-20260116-0801 • Create PR ➔

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Task Completed: String Utility Function to Truncate Text

Summary

Issue #46 has been successfully implemented. I've created a new string utility function that truncates text to a specified length with customizable suffix.

What Was Implemented

1. String Utility Function (lib/utils/string.ts)

• truncate(text: string, maxLength: number, suffix?: string): string
• Implements Zod validation for input parameters
• i18n support for error messages
• Comprehensive JSDoc documentation with examples

2. Comprehensive Test Suite (lib/utils/test.ts)

• ✅ Positive cases: basic truncation, custom suffix, edge cases
• ✅ Negative cases: invalid maxLength values (0, negative, decimal)
• ✅ i18n tests: English and Japanese error messages
• ✅ Special cases: empty strings, long texts, emojis, Japanese text
• All tests passed successfully

3. i18n Support

• Added validation error messages to locales/en.json and locales/ja.json
• Dynamic error message generation based on current locale

Examples

truncate("Hello World", 5)         // => "Hello..."
truncate("Hi", 10)                 // => "Hi"
truncate("Hello World", 5, "…")    // => "Hello…"

Quality Checks

• ✅ Formatting: deno fmt passed (via pre-commit hook)
• ✅ Linting: deno lint passed (via pre-commit hook)
• ✅ Tests: deno test passed (via pre-push hook)
• ✅ Follows CLAUDE.md guidelines:
  • JSDoc comments in Japanese
  • Zod validation for inputs
  • i18n for error messages
  • Comprehensive test coverage

Todo List

• Read CLAUDE.md to understand project conventions
• Explore existing project structure
• Create lib/utils directory
• Add i18n messages to locales files
• Create lib/utils/string.ts with truncate function
• Create lib/utils/test.ts with comprehensive tests
• Run formatting, linting, and tests
• Commit and push changes
• Provide PR creation link

Create Pull Request

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