codePoint top-level constant

String const codePoint

This pattern identifies two main groups of characters:

1. Characters outside the surrogate pair range ([^\uD800-\uDFFF]). This includes most of the Basic Multilingual Plane (BMP) characters, except surrogate pairs.

2. Valid surrogate pairs ([\uD800-\uDBFF][\uDC00-\uDFFF]). In UTF-16 encoding, a surrogate pair is composed of a high surrogate (\uD800-\uDBFF) followed by a low surrogate (\uDC00-\uDFFF). This combination represents characters outside the BMP, especially those from the Supplementary Multilingual Plane (SMP).

Use this pattern to safely iterate over strings containing both BMP and SMP characters without breaking apart valid surrogate pairs.

Implementation

const codePoint = r'(?:[^\uD800-\uDFFF]|[\uD800-\uDBFF][\uDC00-\uDFFF])';