@3rd/supports-color

Detect whether a terminal supports color

Install

npm install @3rd/supports-color

Usage

import supportsColor from '@3rd/supports-color';

if (supportsColor.stdout) {
	console.log('Terminal stdout supports color');
}

if (supportsColor.stdout.has256) {
	console.log('Terminal stdout supports 256 colors');
}

if (supportsColor.stderr.has16m) {
	console.log('Terminal stderr supports 16 million colors (truecolor)');
}

API

Returns an object with a stdout and stderr property for testing either streams. Each property is an Object, or false if color is not supported.

The stdout/stderr objects specifies a level of support for color through a .level property and a corresponding flag:

• .level = 1 and .hasBasic = true: Basic color support (16 colors)
• .level = 2 and .has256 = true: 256 color support
• .level = 3 and .has16m = true: Truecolor support (16 million colors)

Custom instance

The package also exposes the named export createSupportColor function that takes an arbitrary write stream (for example, process.stdout) and an optional options object to (re-)evaluate color support for an arbitrary stream.

import {createSupportsColor} from '@3rd/supports-color';

const stdoutSupportsColor = createSupportsColor(process.stdout);

if (stdoutSupportsColor) {
	console.log('Terminal stdout supports color');
}

// `stdoutSupportsColor` is the same as `supportsColor.stdout`

The options object supports a single boolean property sniffFlags. By default it is true, which instructs the detection to sniff process.argv for the multitude of --color flags (see Info below). If false, then process.argv is not considered when determining color support.

Info

It obeys the --color and --no-color CLI flags.

For situations where using --color is not possible, use the environment variable FORCE_COLOR=1 (level 1), FORCE_COLOR=2 (level 2), or FORCE_COLOR=3 (level 3) to forcefully enable color, or FORCE_COLOR=0 to forcefully disable. The use of FORCE_COLOR overrides all other color support checks.

Explicit 256/Truecolor mode can be enabled using the --color=256 and --color=16m flags, respectively.

Related

• supports-color-cli - CLI for this module
• chalk - Terminal string styling done right
• is-unicode-supported - Detect whether the terminal supports Unicode
• is-interactive - Check if stdout or stderr is interactive

Maintainers

• Sindre Sorhus
• Josh Junon