ansi-fragments

ansi-fragments

A tiny library with builders to help making logs/CLI pretty with a nice DX.

Installation

yarn add ansi-fragments

Usage

import { color, modifier, pad, container } from 'ansi-fragments';

const prettyLog = (level, message) => container(
  color('green', modifier('italic', level)),
  pad(1),
  message
).build();

console.log(prettyLog('success', 'Yay!'));

API

Each fragment implements IFragment interface:

interface IFragment {
  build(): string;
}

The build method is responsible for traversing the tree of fragments and create a string representation with ANSI escape codes.

color(ansiColor: AnsiColor, ...children: Array<string | IFragment>): IFragment

Creates fragment for standard ANSI colors.

color('red', 'Oh no');
color('bgBlue', color('brightBlue', 'Hey'));
color('green', modifier('bold', 'Sup!'));

modifier(ansiModifier: AnsiModifier, ...children: Array<string | IFragment>): IFragment

Creates fragment for standard ANSI modifiers: dim, bold, hidden, italic, underline, strikethrough.

modifier('underline', 'Hello', 'World');
modifier('italic', modifier('bold', 'Hey'));
modifier('bold', color('green', 'Sup!'));

container(...children: Array<string | IFragment>): IFragment

Creates fragment, which sole purpose is to hold and build nested fragments.

container(
  color('gray', '[08/01/18 12:00]'),
  pad(1),
  color('green', 'success'),
  pad(1),
  'Some message'
)

pad(count: number, separator?: string): IFragment

Creates fragment, which repeats given separator (default: ) given number of times.

pad(1);
pad(2, '#')
pad(1, '\n')

fixed(value: number, bias: 'start' | 'end', ...children: Array<string | IFragment>): IFragment

Creates fragment, which makes sure the children will always build to given number of non-ANSI characters. It will either trim the results or add necessary amount of spaces. The bias control if trimming/padding should be done at the start of the string representing built children or at the end.

fixed(5, 'start', 'ERR'); // => '  ERR'
fixed(8, 'end', color('green', 'success')); // equals to color('green', 'success') + ' '
fixed(10, 'end', 'Hello', pad(2), 'World') // => 'Hello  Wor'