textutil

func TruncateRunes ¶

func TruncateRunes(s string, max int, suffix string) string

TruncateRunes caps s at max runes, appending suffix when it was cut. Truncation happens on rune (not byte) boundaries: much of the bot's content is Russian, and a byte-level slice can split a multibyte rune and corrupt the tail.

Allocation-free until the cut: callers pass multi-megabyte strings on hot paths (serialized LLM request bodies with base64 media), where a []rune(s) conversion would transiently cost ~4x the input size.