Colorized output in nodejs

color.js

var color, i;

// Notice: octal literals are not allowed in strict mode.
function colorize(color, output) {
    return ['\033[', color, 'm', output, '\033[0m'].join('');
}

for (i = 0; i < 100; i += 1) {
    color = Math.random() > 0.9 ? 91 : 92; // 91 - red, 92 - green
    process.stdout.write( colorize(color, '●') );
}
process.stdout.write('\n');

Nice !!

For use in strict mode, instead of using the \033 escape mode, \x1b can be used:

Escape sequence	Text attributes
\x1b[0m	All attributes off (reset)
\x1b[1m	Bold on(enable foreground intensity)
\x1b[4m	Underline on
\x1b[5m	Blink on (enable background intensity)
\x1b[21m	Bold off (disable foreground intensity)
\x1b[24m	Underline off
\x1b[25m	Blink off (disable background intensity)

Escape sequence	Foreground colors
\x1b[30m	Black
\x1b[31m	Red
\x1b[32m	Green
\x1b[33m	Yellow
\x1b[34m	Blue
\x1b[35m	Magenta
\x1b[36m	Cyan
\x1b[37m	White
\x1b[39m	Default (foreground color at startup)
\x1b[90m	Light Gray
\x1b[91m	Light Red
\x1b[92m	Light Green
\x1b[93m	Light Yellow
\x1b[94m	Light Blue
\x1b[95m	Light Magenta
\x1b[96m	Light Cyan
\x1b[97m	Light White

Escape sequence	Background colors
\x1b[40m	Black
\x1b[41m	Red
\x1b[42m	Green
\x1b[43m	Yellow
\x1b[44m	Blue
\x1b[45m	Magenta
\x1b[46m	Cyan
\x1b[47m	White
\x1b[49m	Default (background color at startup)
\x1b[100m	Light Gray
\x1b[101m	Light Red
\x1b[102m	Light Green
\x1b[103m	Light Yellow
\x1b[104m	Light Blue
\x1b[105m	Light Magenta
\x1b[106m	Light Cyan
\x1b[107m	Light White

Source: https://gist.github.com/raghav4/48716264a0f426cf95e4342c21ada8e7