document.contains/implementation.js

Polyfill/shim for `document.contains`

'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;
};