oli-colors/index.js

lets you use terminal colors esser

/**
 * @typedef {(text: string) => string} ColorFn
 */

/**
 * @type {{
 *  reset: ColorFn,
 *  bold: ColorFn,
 *  dim: ColorFn,
 *  italic: ColorFn,
 *  underline: ColorFn,
 *  blink: ColorFn,
 *  inverse: ColorFn,
 *  hidden: ColorFn,
 *  strikethrough: ColorFn,
 *  black: ColorFn,
 *  red: ColorFn,
 *  green: ColorFn,
 *  yellow: ColorFn,
 *  blue: ColorFn,
 *  magenta: ColorFn,
 *  cyan: ColorFn,
 *  white: ColorFn,
 *  brightBlack: ColorFn,
 *  brightRed: ColorFn,
 *  brightGreen: ColorFn,
 *  brightYellow: ColorFn,
 *  brightBlue: ColorFn,
 *  brightMagenta: ColorFn,
 *  brightCyan: ColorFn,
 *  brightWhite: ColorFn,
 *  bgBlack: ColorFn,
 *  bgRed: ColorFn,
 *  bgGreen: ColorFn,
 *  bgYellow: ColorFn,
 *  bgBlue: ColorFn,
 *  bgMagenta: ColorFn,
 *  bgCyan: ColorFn,
 *  bgWhite: ColorFn,
 *  bgBrightBlack: ColorFn,
 *  bgBrightRed: ColorFn,
 *  bgBrightGreen: ColorFn,
 *  bgBrightYellow: ColorFn,
 *  bgBrightBlue: ColorFn,
 *  bgBrightMagenta: ColorFn,
 *  bgBrightCyan: ColorFn,
 *  bgBrightWhite: ColorFn
 * }}
 */
const ESC = '\x1b[';
const RESET = `${ESC}0m`;

const EFFECT_CODES = {
  reset: 0,
  bold: 1,
  dim: 2,
  italic: 3,
  underline: 4,
  blink: 5,
  inverse: 7,
  hidden: 8,
  strikethrough: 9,
};

const FG_CODES = {
  black: 30,
  red: 31,
  green: 32,
  yellow: 33,
  blue: 34,
  magenta: 35,
  cyan: 36,
  white: 37,
  brightBlack: 90,
  brightRed: 91,
  brightGreen: 92,
  brightYellow: 93,
  brightBlue: 94,
  brightMagenta: 95,
  brightCyan: 96,
  brightWhite: 97,
};

const BG_CODES = {
  black: 40,
  red: 41,
  green: 42,
  yellow: 43,
  blue: 44,
  magenta: 45,
  cyan: 46,
  white: 47,
  brightBlack: 100,
  brightRed: 101,
  brightGreen: 102,
  brightYellow: 103,
  brightBlue: 104,
  brightMagenta: 105,
  brightCyan: 106,
  brightWhite: 107,
};

const ALL_CODES = {
  ...EFFECT_CODES,
  ...FG_CODES,
  ...Object.fromEntries(
    Object.entries(BG_CODES).map(([k, v]) => [
      'bg' + k.charAt(0).toUpperCase() + k.slice(1),
      v,
    ])
  ),
};

/**
 * Applies ANSI codes to the text
 * @param {number[]} codes
 * @param {string} text
 */
function applyStyles(codes, text) {
  if (!text) return '';
  const prefix = ESC + codes.join(';') + 'm';
  return prefix + text + RESET;
}

/**
 * Chainable Proxy function to enable .bold.red.bgYellow('text') usage
 * @param {number[]} styles 
 */
function createChain(styles = []) {
  const handler = {
    get(target, prop) {
      if (prop === 'toString' || prop === 'valueOf' || prop === Symbol.toPrimitive) {
        return () => styles.join(';');
      }
      if (ALL_CODES[prop] !== undefined) {
        return createChain([...styles, ALL_CODES[prop]]);
      }
      return undefined;
    },
    apply(target, thisArg, args) {
      return applyStyles(styles, args[0]);
    },
  };
  function f(text) {
    return applyStyles(styles, text);
  }
  return new Proxy(f, handler);
}

/**
 * @typedef {(text: string) => string & {[key in keyof typeof ALL_CODES]: any}} Chainable
 * @type {Chainable}
 */
const e = createChain();

module.exports = e;