index.js

'use strict';
var isUtf8 = require('is-utf8');

module.exports = function (x) {
	// Catches EFBBBF (UTF-8 BOM) because the buffer-to-string
	// conversion translates it to FEFF (UTF-16 BOM)
	if (typeof x === 'string' && x.charCodeAt(0) === 0xFEFF) {
		return x.slice(1);
	}

	if (Buffer.isBuffer(x) && isUtf8(x) &&
		x[0] === 0xEF && x[1] === 0xBB && x[2] === 0xBF) {
		return x.slice(3);
	}

	return x;
};