flutter pub add characters根據套件公開資料產生的選型評估，僅供參考。
characters 套件為 Dart 提供 Unicode 意識的字串操作，確保索引與取代等運算能尊重字形群組——由多個碼點組成的單一可見字元。此套件讓國際化應用中的文字處理更安全且精確，特別是在使用者輸入複雜文字或表情符號時。該套件擴充 String 並提供 Characters 類別，正確處理組合標記與代理對等邊際情況。
以下為關聯原始碼儲存庫的 README 原文快照，最新內容請造訪原始碼儲存庫。
This repository is home to various Dart packages under the dart.dev publisher.
| Package | Description | Issues | Version |
|---|---|---|---|
| args | Library for defining parsers for parsing raw command-line arguments into a set of options and values using GNU and POSIX style options. |  |
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| async | Utility functions and classes related to the 'dart:async' library. | |
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| characters | String replacement with operations that are Unicode/grapheme cluster aware. | |
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| collection | Collections and utilities functions and classes related to collections. | |
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| convert | Utilities for converting between data representations. Provides a number of Sink, Codec, Decoder, and Encoder types. | |
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| crypto | Implementations of SHA, MD5, and HMAC cryptographic functions. | |
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| fixnum | Library for 32- and 64-bit signed fixed-width integers with consistent behavior between native and JS runtimes. | |
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| lints | Official Dart lint rules. Defines the 'core' and 'recommended' set of lints suggested by the Dart team. | |
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| logging | Provides APIs for debugging and error logging, similar to loggers in other languages, such as the Closure JS Logger and java.util.logging.Logger. | |
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| os_detect | Platform independent OS detection. | |
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| path | A string-based path manipulation library. | |
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| platform | A pluggable, mockable platform information abstraction for Dart. | |
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| typed_data | Utility functions and classes related to the dart:typed_data library. | |
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For information about our publishing automation and release process, see https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.
For additional information about contributing, see our contributing page.