graphemes

Emoji- and grapheme-aware string helpers, so length, slice, truncate and reverse don't break emoji, flags, skin tones or ZWJ sequences (👨‍👩‍👧‍👦).

In JavaScript, 'a👍b'.length is 4, and naive slice/reverse can split an emoji in half. graphemes counts and cuts by user-perceived characters using Intl.Segmenter (with a code-point fallback). Zero dependencies.

Install

npm install @suzukihayate/graphemes

Usage

import { length, slice, truncate, reverse, toGraphemes, at } from '@suzukihayate/graphemes';

length('a👍b');          // 3   (native .length is 4)
length('👨‍👩‍👧‍👦');         // 1   (a single ZWJ grapheme)

slice('a👍b😀c', 1, 3);  // "👍b"
reverse('a👍b');         // "b👍a"  (emoji stays intact)
truncate('a👍b😀c', 3);  // "a👍…"  (no broken emoji)
at('a👍b', 1);           // "👍"

toGraphemes('a👍b');     // ["a", "👍", "b"]

API

• toGraphemes(str) → string[]
• length(str) → grapheme count
• slice(str, start?, end?) → grapheme-based slice (negative indices ok)
• at(str, index) → grapheme at index (supports negative)
• reverse(str) → reverse by graphemes
• truncate(str, max, { ellipsis? }) → truncate to ≤ max graphemes incl. ellipsis

Uses Intl.Segmenter when available (Node 16+, modern browsers). Falls back to code points otherwise.

Test

node --test

License

MIT © 2026 Hayate Suzuki