truncate

Truncates text to a maximum grapheme length including its marker.

Code

truncate.ts

const segmenter =
  typeof Intl !== "undefined" && typeof Intl.Segmenter === "function"
    ? new Intl.Segmenter(undefined, { granularity: "grapheme" })
    : undefined;

const splitGraphemes = (value: string): string[] => {
  if (!segmenter) return Array.from(value);
  return Array.from(segmenter.segment(value), ({ segment }) => segment);
};

/** Truncates text to a maximum grapheme length, including its omission marker. */
export const truncate = (
  value: string,
  maxLength: number,
  omission: string = "…"
): string => {
  if (!Number.isSafeInteger(maxLength) || maxLength < 0) {
    throw new RangeError("maxLength must be a non-negative safe integer");
  }

  const graphemes = splitGraphemes(value);
  if (graphemes.length <= maxLength) return value;

  const marker = splitGraphemes(omission);
  if (marker.length >= maxLength) return marker.slice(0, maxLength).join("");
  return graphemes.slice(0, maxLength - marker.length).join("") + omission;
};

Download

wget

Terminal

wget -O src/lib/truncate.ts https://raw.githubusercontent.com/jrTilak/lazykit/HEAD/registry/functions/truncate.ts

degit

Terminal

temp_dir="$(mktemp -d)" && bunx degit jrTilak/lazykit/registry/functions "$temp_dir" && mv "$temp_dir/truncate.ts" src/lib/truncate.ts && rm -r "$temp_dir"

Examples

truncate.example.ts

import { truncate } from "./truncate";

const label = truncate("A very long label", 10);
// "A very lo…"

const familyLabel = truncate("👨‍👩‍👧‍👦 family account", 10);
// "👨‍👩‍👧‍👦 family …"

Props

• value (string) — Text to shorten.
• maxLength (number) — Non-negative safe-integer maximum number of visible characters.
• omission (string) — Marker included within the maximum, defaulting to ….
• Uses Intl.Segmenter to preserve emoji sequences, flags, and combining marks. Environments without it fall back to Unicode code points.