Just reads a list from standard in to an array.

file_map.js

#!/usr/bin/env node

// --Usage--
// Bash: find `pwd` -type f | ./file_map.js
// Fish: find (pwd) -type f | ./file_map.js

const readline = require('readline');
const files = [];

var rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  terminal: false
});

rl.on('line', files.push.bind(files));

rl.on('close', () => console.log(`Collected ${files.length} files`));