'use strict'; module.exports = function contains(other) { if (arguments.length < 1) { throw new TypeError('1 argument is required'); } if (typeof other !== 'object') { throw new TypeError('Argument 1 (”other“) to Node.contains must be an instance of Node'); } var node = other; do { if (this === node) { return true; } if (node) { node = node.parentNode; } } while (node); return false; };