ansis

Bug Fixes

• color-support: prevent colors in piped or redirected output when COLORTERM is set, #54

• color-support: detect the color level for FORCE_COLOR=true and --color in non-TTY output

Behavior

Colors are enabled only for a TTY, CI, and the PM2 and Next.js runtimes. Output to a pipe or a file has no colors, even when COLORTERM is set. COLORTERM sets only the color level.

FORCE_COLOR=true, FORCE_COLOR= and --color in non-TTY output now detect the level from the environment (COLORTERM, TERM, Windows) instead of always using 16 colors.

Upgrade note

If your tests relied on COLORTERM to get colors, set FORCE_COLOR instead, for example FORCE_COLOR=3 npm test. See Testing.

Bug fixes

1. TERM=dumb now disables colors during auto-detection

Ansis now treats TERM=dumb as no color before applying COLORTERM, CI detection, PM2, Next.js runtime detection, and platform-specific defaults, #49.

Before, COLORTERM=truecolor or other later auto-detection checks could still enable colors even when the environment reported TERM=dumb. This could produce visible ANSI escape codes in environments such as Emacs M-x compile.

COLORTERM remains a color capability hint. FORCE_COLOR keeps the highest priority and can still explicitly enable colors.

* - Depends on additional conditions.

Bug fixes

1. reset no longer appends a closing sequence

Before, reset was treated like any other style with an open and a close code, so it wrapped the value on both sides. That produced extra reset sequences in chained, nested, template literal, and multiline compositions, and the output did not match what a single reset should do.

Before:

ansis.reset('foo');
// "\x1b[0mfoo\x1b[0m"

Now:

ansis.reset('foo');
// "\x1b[0mfoo"

If you need a trailing reset, add it explicitly:

ansis.reset`foo ${ansis.red('bar')} baz` + ansis.reset();
// "\x1b[0mfoo \x1b[31mbar\x1b[39m baz\x1b[0m"

ansis.reset() without argument returns just the reset code \x1b[0m, which makes appending it easy.

2. strip() removes OSC 8 hyperlink sequences

strip() did not clear the OSC 8 sequences produced by link().
It now removes them and returns plain text:

ansis.strip(ansis.link('https://example.com', 'text'));
// "text"

3. No style leakage between instances with different color levels

Styles created on one Ansis instance could appear on another instance that was created with a different color level. That could give output rendered at the wrong color level.
Now, instances are isolated, so each one keeps its own styles and level.

import { Ansis } from 'ansis';

const noColor = new Ansis(0);
const color = new Ansis(1);

// Fixed: chained styles on `noColor` stay unstyled.
noColor.red.bold('foo');
// -> 'foo'

// Reference: a colored instance still renders the same chain with ANSI styles.
color.red.bold('foo');
// -> '\x1b[31m\x1b[1mfoo\x1b[22m\x1b[39m'

4. .extend() no longer affects other instances

Calling .extend() on one instance could override styles on other instances that use a different color level.
Now, the .extend() method stays local to the instance on which it is called.

import { Ansis } from 'ansis';

const trueColor = new Ansis(3);
const noColor = new Ansis(0);

trueColor.extend({
  pink: '#ff69b4',
});

// Fixed: `extend()` stays local to `trueColor`.
trueColor.red('foo');
// -> '\x1b[31mfoo\x1b[39m'

// Fixed: extending `trueColor` does not leak styles or color level into `noColor`.
noColor.red('foo');
// -> 'foo'