'use strict';

var callBound = require('call-bind/callBound');
var $byteLength = callBound('ArrayBuffer.prototype.byteLength', true);

var isArrayBuffer = require('is-array-buffer');

module.exports = function byteLength(ab) {
	if (!isArrayBuffer(ab)) {
		return NaN;
	}
	return $byteLength ? $byteLength(ab) : ab.byteLength;
}; // in node < 0.11, byteLength is an own nonconfigurable property