The fastest Node.js library for formatting terminal text with ANSI colors~!
## Features
* No dependencies
* Super [lightweight](#load-time) & [performant](#performance)
* Supports [nested](#nested-methods) & [chained](#chained-methods) colors
* No `String.prototype` modifications
* Conditional [color support](#conditional-support)
* [Fully treeshakable](#individual-colors)
* Familiar [API](#api)
---
As of `v3.0` the Chalk-style syntax (magical getter) is no longer used.
Please visit [History](#history) for migration paths supporting that syntax.
---
## Install
```
$ npm install --save kleur
```
## Usage
```js
import kleur from 'kleur';
// basic usage
kleur.red('red text');
// chained methods
kleur.blue().bold().underline('howdy partner');
// nested methods
kleur.bold(`${ white().bgRed('[ERROR]') } ${ kleur.red().italic('Something happened')}`);
```
### Chained Methods
```js
const { bold, green } = require('kleur');
console.log(bold().red('this is a bold red message'));
console.log(bold().italic('this is a bold italicized message'));
console.log(bold().yellow().bgRed().italic('this is a bold yellow italicized message'));
console.log(green().bold().underline('this is a bold green underlined message'));
```
### Nested Methods
```js
const { yellow, red, cyan } = require('kleur');
console.log(yellow(`foo ${red().bold('red')} bar ${cyan('cyan')} baz`));
console.log(yellow('foo ' + red().bold('red') + ' bar ' + cyan('cyan') + ' baz'));
```
### Conditional Support
Toggle color support as needed; `kleur` includes simple auto-detection which may not cover all cases.
> **Note:** Both `kleur` and `kleur/colors` share the same detection logic.
```js
import kleur from 'kleur';
// manually disable
kleur.enabled = false;
// or use another library to detect support
kleur.enabled = require('color-support').level > 0;
console.log(kleur.red('I will only be colored red if the terminal supports colors'));
```
> **Important:**
Colors will be disabled automatically in non [TTY contexts](https://nodejs.org/api/process.html#process_a_note_on_process_i_o). For example, spawning another process or piping output into another process will disable colorization automatically. To force colors in your piped output, you may do so with the `FORCE_COLOR=1` environment variable:
```sh
$ node app.js #=> COLORS
$ node app.js > log.txt #=> NO COLORS
$ FORCE_COLOR=1 node app.js > log.txt #=> COLORS
$ FORCE_COLOR=0 node app.js > log.txt #=> NO COLORS
```
## API
Any `kleur` method returns a `String` when invoked with input; otherwise chaining is expected.
> It's up to the developer to pass the output to destinations like `console.log`, `process.stdout.write`, etc.
The methods below are grouped by type for legibility purposes only. They each can be [chained](#chained-methods) or [nested](#nested-methods) with one another.
***Colors:***
> black — red — green — yellow — blue — magenta — cyan — white — gray — grey
***Backgrounds:***
> bgBlack — bgRed — bgGreen — bgYellow — bgBlue — bgMagenta — bgCyan — bgWhite
***Modifiers:***
> reset — bold — dim — italic* — underline — inverse — hidden — strikethrough*
* Not widely supported
## Individual Colors
When you only need a few colors, it doesn't make sense to import _all_ of `kleur` because, as small as it is, `kleur` is not treeshakeable, and so most of its code will be doing nothing. In order to fix this, you can import from the `kleur/colors` submodule which _fully_ supports tree-shaking.
The caveat with this approach is that color functions **are not** chainable~!
Each function receives and colorizes its input. You may combine colors, backgrounds, and modifiers by nesting function calls within other functions.
```js
// or: import * as kleur from 'kleur/colors';
import { red, underline, bgWhite } from 'kleur/colors';
red('red text');
//~> kleur.red('red text');
underline(red('red underlined text'));
//~> kleur.underline().red('red underlined text');
bgWhite(underline(red('red underlined text w/ white background')));
//~> kleur.bgWhite().underline().red('red underlined text w/ white background');
```
> **Note:** All the same [colors, backgrounds, and modifiers](#api) are available.
***Conditional Support***
The `kleur/colors` submodule also allows you to toggle color support, as needed.
It includes the same initial assumptions as `kleur`, in an attempt to have colors enabled by default.
Unlike `kleur`, this setting exists as `kleur.$.enabled` instead of `kleur.enabled`:
```js
import * as kleur from 'kleur/colors';
// or: import { $, red } from 'kleur/colors';
// manually disabled
kleur.$.enabled = false;
// or use another library to detect support
kleur.$.enabled = require('color-support').level > 0;
console.log(red('I will only be colored red if the terminal supports colors'));
```
## Benchmarks
> Using Node v10.13.0
### Load time
```
chalk :: 5.303ms
kleur :: 0.488ms
kleur/colors :: 0.369ms
ansi-colors :: 1.504ms
```
### Performance
```
# All Colors
ansi-colors x 177,625 ops/sec ±1.47% (92 runs sampled)
chalk x 611,907 ops/sec ±0.20% (92 runs sampled)
kleur x 742,509 ops/sec ±1.47% (93 runs sampled)
kleur/colors x 881,742 ops/sec ±0.19% (98 runs sampled)
# Stacked colors
ansi-colors x 23,331 ops/sec ±1.81% (94 runs sampled)
chalk x 337,178 ops/sec ±0.20% (98 runs sampled)
kleur x 78,299 ops/sec ±1.01% (97 runs sampled)
kleur/colors x 104,431 ops/sec ±0.22% (97 runs sampled)
# Nested colors
ansi-colors x 67,181 ops/sec ±1.15% (92 runs sampled)
chalk x 116,361 ops/sec ±0.63% (94 runs sampled)
kleur x 139,514 ops/sec ±0.76% (95 runs sampled)
kleur/colors x 145,716 ops/sec ±0.97% (97 runs sampled)
```
## History
This project originally forked [`ansi-colors`](https://github.com/doowb/ansi-colors).
Beginning with `kleur@3.0`, the Chalk-style syntax (magical getter) has been replaced with function calls per key:
```js
// Old:
c.red.bold.underline('old');
// New:
c.red().bold().underline('new');
```
> As I work more with Rust, the newer syntax feels so much better & more natural!
If you prefer the old syntax, you may migrate to `ansi-colors` or newer `chalk` releases.
Versions below `kleur@3.0` have been officially deprecated.
## License
MIT © [Luke Edwards](https://lukeed.com)
