var fs = require('fs');
var isUtf8 = require('is-utf8');
var ansi = fs.readFileSync('ansi.txt');
var utf8 = fs.readFileSync('utf8.txt');

console.log('ansi.txt is utf8: '+isUtf8(ansi));
console.log('utf8.txt is utf8: '+isUtf8(utf8));