Linux bash color console in nodejs

colorconsole.js

/*
  Allows coloring linux console text with nodejs.
    Color codes are loaded into a table of 8 rows
      with each row containing 64 columns.

Examples:
  Save this file as 'colorconsole.js'
   then run 'node ./colorconsole.js'

Usage:
  let cc = new ColorConsole;
  cc.etx(156); // set default color
  cc.stx(3).write('brown on yellow').nl()
    .write('now change midstream ')
    .stx(316).write('italics')
    .stx(3).write(' and back.')
    .nl().nl();

  cc.log('log() does auto new-line!');

API:
  All functions can be chained.
  Functions starting with _ are used internally.

  // Create a color console.
  let cc = new ColorConsole;

  // Sets current color code
  cc.stx(r, c)

  // Sets default color code
  cc.etx(r, c)

  // Write a new-line, handy when using write()
  cc.nl()

  // Write the text unformatted in current color
  cc.write('text')

  // Log the text formatted via console.log()
  cc.log('text')

Description:
  The current color is set and remains active until
    is set again with the start-of-text stx() function.
  Text given in write() and log() are color coded with
    the current color until a new stx() is called.
  Each text block is terminated with the color code
    set by the end-of-text etx() function, which is
    effectively the default color.
  Color codes are in a table that is referenced by
    stx(r, c) and etx(r, c)
        r = row 0 - 7
        c = column 0 - 63
            or
        r = rcc where r=row and cc = column
  The functions to write text are :
    write(text) and log(text).
        text = text to display
    write() bypasses text formating
    log() formats text via nodejs console.log()


  The Test class displays handy charts which show the
    text colors for row,col or rcc color code references.
*/

// Linux bash color console
class ColorConsole {
  constructor(stx = 156, etx = 156) {

    this.ESC = String.fromCharCode(27);
    this.NL =  String.fromCharCode(10);

    this.colors;
    this._createColors();

    this.ccode = { stx: '', etx: '' };
    this._coord(stx, null, true);
    this._coord(etx, null, false);
  }

  // Build table of the color codes
  _createColors() {
    let codes = [];
    for (let x=0; x<8; x++) {
      let code = [];
      for (let i=30; i<38; i++) {
        for (let a=40; a<48; a++) {
          code.push(`[${x};${i};${a}m`)
        }
      }
      codes.push(code);
    }
    this.colors = codes;
    return this;
  }

  // Allows single number to reference color codes
  // ex: r can be 156 which becomes r=1 c=56
  _coord(r, c, toStx) {
    if (typeof c !== 'number') {
      let x = r; r = Math.floor(x/100); c = x-(r*100);
    }
    if (toStx) {
      this.ccode.stx = this.ESC + this.colors[r][c];
    }
    else {
      this.ccode.etx = this.ESC + this.colors[r][c];
    }
    return this;
  }

  // Set start-of-text code by ref or row/col
  stx(r, c) { return this._coord(r, c, true); }

  // Set end--of-text code by ref or row/col
  etx(r, c) { return this._coord(r, c, false); }

  // Write a new-line
  nl() {
    process.stdout.write(this.ccode.etx + this.NL + this.ccode.etx);
    return this;
  }

  // Write the text unformatted in current color
  write(text) {
    process.stdout.write(this.ccode.stx + text + this.ccode.etx);
    return this;
  }

  // Log the text formatted in the current color
  log(text) {
    console.log(this.ccode.stx + text + this.ccode.etx);
    return this;
  }
}

// ------

class Test {
  constructor(cc = new ColorConsole) { this.cc = cc; }

  // show list of console color codes
  list() { console.log(this.cc.colors); }

  // Show row/col chart on console
  chart() {
    console.log('\nBy row/column:');
    for (let r=0; r<8; r++) { // row 0 - 7
      this.cc.nl();
      for (let c=0; c<64; c++) { // col 0 - 63
        if (!(c % 8)) { this.cc.nl(); } // new-line every 8 codes
        // display the table row/col's format
        // followed by a normal space
        let ca = /..$/.exec('0' + c); // right 2 chars
        this.cc.stx(r, c).write(' ' + r + ',' + ca + ' ')
          .stx(56).write(' ');
      }
    }
    this.cc.nl().nl();
  }

  // Show single number reference chart on console
  chart2() {
    console.log('\nBy single reference:');
    for (let r=0; r<800; r+=100) { // row 0 - 7
      this.cc.nl();
      for (let c=0; c<64; c++) { // col 0 - 63
        if (!(c % 8)) { this.cc.write(' ').nl(); } // new-line every 8 codes
        let ca = /...$/.exec('   ' + String(r+c)); // right 3 chars
        // display the table single reference format
        // followed by a normal space
        this.cc.stx(r+c).write(' ' + ca + ' ')
          .stx(0, 56).write(' ');
      }
    }
    this.cc.nl().nl();
  }
}

let test = new Test;

test.chart();  // Access by row/col  ex: (3, 45, 'text')

test.chart2(); // Access by single ref ex: (345,'text')

test.cc.stx(3).write('old yellow/brown dog').nl();

let  f = 'formatted';
test.cc.stx(0, 5).log(`this is ${f}`);
test.cc.log('Uses current color code');

test.cc.stx(4).log('this is just a line');

  // Usage examples
    let cc = new ColorConsole;
    cc.etx(156); // set default color
    cc.stx(3).write('brown on yellow').nl()
      .write('now change midstream ')
      .stx(316).write('italics')
      .stx(3).write(' and back.')
      .nl().nl();

    cc.log('log() does auto new-line!');

// test.list();