#URange

A half-open UTF-16 code-unit range: [start, end). start is inclusive, end is exclusive. Used by paragraph hit-testing and word/line boundary APIs to describe substrings of the original text.

const r = { start: 0, end: 5 };  // covers code units 0..4 (5 chars)

The half-open convention matches String.prototype.slice(start, end). Distinct from Range (closed first/last).

#Fields

#See also

• Range — closed integer range (paragraph runs).