// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license. export function getDOMStringList(arr: string[]): DOMStringList { Object.defineProperties(arr, { contains: { value(searchElement: string): boolean { return arr.includes(searchElement); }, enumerable: true, }, item: { value(idx: number): string | null { return idx in arr ? arr[idx] : null; }, }, }); return arr as string[] & DOMStringList; }