@neotales/ansi

Overview

Cross-runtime ANSI color styles, terminal capability detection, and mutable terminal settings. The style helpers work in Deno, Node.js, Bun, browsers, and Cloudflare Workers. Terminal detection is meaningful only in runtimes with a terminal; browser and Worker environments default to plain text.

Installation

deno add jsr:@neotales/ansi
npm install @neotales/ansi

Styles

import { apply, bgBlue, blue, bold, green, stripAnsiCode } from "@neotales/ansi";

console.log(blue("information"));
console.log(green("success"));
console.log(apply("notice", bold, blue, bgBlue));

stripAnsiCode("\x1b[31merror\x1b[39m"); // "error"

Set setColorEnabled(false) to suppress all escape codes. Pass undefined to restore automatic enablement from AnsiSettings.current.mode. The override is module-global, so applications should restore it after a temporary change.

Terminal Detection

detectMode() checks --color, --color=<level>, --no-color, NO_COLOR, FORCE_COLOR, common CI variables, COLORTERM, and TERM. Color levels accept 16-color, 256-color, and truecolor aliases. AnsiSettings.current holds the shared detected mode and controls adaptive custom colors.

import { AnsiModes, AnsiSettings, defineColor, yellow } from "@neotales/ansi";

AnsiSettings.current = new AnsiSettings(AnsiModes.TwentyFourBit);
const orange = defineColor(0xff8c00, 208, yellow);
console.log(orange("warning"));

Hyperlinks

link creates an OSC-8 terminal hyperlink when colors and AnsiSettings.current.links are enabled. URLs are stripped of terminal control characters before output.

import { link } from "@neotales/ansi";

console.log(link("Neotales", "https://github.com/neotales/js-std"));

Extended Colors

import { bgRgb24, rgb8, rgb24 } from "@neotales/ansi";

rgb8("palette", 208);
rgb24("true color", { r: 255, g: 140, b: 0 });
bgRgb24("background", 0x123456);

rgb8, rgb24, and their background variants clamp channels and palette indexes to valid ANSI ranges. rgb24To8 downgrades true color to the 256-color palette.

Browser And Workers

Browsers and Cloudflare Workers can produce and strip ANSI sequences, but they have no terminal to detect. Styles default to disabled there unless an application explicitly calls setColorEnabled(true). ANSI escapes are not CSS styling and will not affect browser-rendered text.

License

MIT