Custom cowsay files with configurable eyes

The npm cowsay package supports loading custom .cow files from any path, not just the built-in ones. This lets you create modified versions with configurable features like dynamic eyes.

The discovery

Looking at the cowsay source code in lib/cows.js:

if (cow.match(/\\/) || cow.match(/\//)) {
  filePath = cow; // Use as full path if contains slash
} else {
  filePath = path.join(__dirname, "/../cows", cow) + ".cow";
}

Key insight: If the f option contains a / or \, cowsay treats it as a file path instead of looking in node_modules/cowsay/cows/.

Visual examples

Fox awake (nighttime) - wide eyes

 ________________________
< Wa-pa-pa-pa-pa-pa-pow! >
 ------------------------
\
 \
   /\   /\   Todd Vargo
  //\_//\     ____
  \_     _/    /   /
   / * * \    /^^^]
   \_\O/_/    [   ]
    /   \_    [   /
    \     \_  /  /
     [ [ /  \/ _/
    _[ [ \  /_/

Fox sleeping (daytime) - sleepy eyes

 ________
< Zzz... >
 --------
\
 \
   /\   /\   Todd Vargo
  //\_//\     ____
  \_     _/    /   /
   / - - \    /^^^]
   \_\O/_/    [   ]
    /   \_    [   /
    \     \_  /  /
     [ [ /  \/ _/
    _[ [ \  /_/

How to implement

1. Create a custom .cow file

Copy the original and replace hardcoded eyes with $eyes:

# new-cows/fox.cow
$the_cow = <<EOC;
$thoughts
 $thoughts
   /\   /\   Todd Vargo
  //\\_//\\     ____
  \_     _/    /   /
   / $eyes \    /^^^]
   \_\O/_/    [   ]
    /   \_    [   /
    \     \_  /  /
     [ [ /  \/ _/
    _[ [ \  /_/
EOC

2. Use the custom file with configurable eyes

import * as cowsay from "cowsay";

// Load custom cow file (path must contain a slash)
// Set eyes with the 'e' option
console.log(
  cowsay.say({
    text: "Hello!",
    f: "./new-cows/fox.cow",
    e: "* *",
  }),
);

3. Make eyes dynamic

const hour = new Date().getHours();
const isSleeping = hour >= 7 && hour < 19;

const text = isSleeping ? "Zzz..." : "What does the fox say?";
const eyes = isSleeping ? "- -" : "* *";

console.log(
  cowsay.say({
    text: text,
    f: "./new-cows/fox.cow",
    e: eyes,
  }),
);

Available variables in .cow files

Variable	Description	Example
$thoughts	Speech bubble connector	\ or o
$eyes	Two-character eye string	oo, **, ^^
$tongue	Tongue string	U

References

• cowsay npm package
• Original fox ASCII art by Todd Vargo