function

bun.sliceAnsi

function sliceAnsi(

input: string,

start?: number,

end?: number,

options?: string | boolean | SliceAnsiOptions,

ambiguousIsNarrow?: boolean

): string;

Slice a string by visible column width, preserving ANSI escape codes.

Like String.prototype.slice, but indices are terminal column widths (accounting for wide CJK characters, emoji grapheme clusters, and zero-width joiners), and ANSI escape sequences (SGR colors, OSC 8 hyperlinks, etc.) are preserved and correctly re-opened/closed at the slice boundaries.

@param input

The string to slice

@param start

Starting column (default 0). Negative counts from end.

@param end

Ending column, exclusive (default end of string). Negative counts from end.

@param options

Optional behavior flags (such as ellipsis for truncation)

@param ambiguousIsNarrow

ambiguousIsNarrow as a positional arg, usable when the 4th arg is an ellipsis string (or undefined). Lets you pass both options without an object: sliceAnsi(s, 0, n, "\u2026", false).

@returns

The sliced string with ANSI codes intact

import { sliceAnsi } from "bun";

// Plain slice (replaces the `slice-ansi` npm package)
sliceAnsi("hello", 1, 4);                              // "ell"
sliceAnsi("\u001b[31mhello\u001b[39m", 1, 4);          // "\u001b[31mell\u001b[39m"
sliceAnsi("\u5b89\u5b81\u54c8", 0, 4);                 // "\u5b89\u5b81" (CJK: width 2 each)

// Truncation (replaces the `cli-truncate` npm package)
sliceAnsi("unicorn", 0, 4, "\u2026");           // "uni\u2026"
sliceAnsi("unicorn", -4, undefined, "\u2026");  // "\u2026orn"