supports-color

Detect whether a terminal supports color

Install

$ npm install supports-color

Usage

const supportsColor = require('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)

require('supports-color').supportsColor(stream, options?)

Additionally, supports-color exposes the .supportsColor() function that takes an arbitrary write stream (e.g. process.stdout) and an optional options object to (re-)evaluate color support for an arbitrary stream.

For example, require('supports-color').stdout is the equivalent of require('supports-color').supportsColor(process.stdout).

The options object supports a single boolean property sniffFlags. By default it is true, which instructs supportsColor() 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

Maintainers

• Sindre Sorhus
• Josh Junon

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