// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0

import { HttpRequest } from '../../../../../types';

/**
 * Returns signed headers.
 *
 * @param headers `headers` from the request.
 * @returns List of headers included in canonical headers, separated by semicolons (;). This indicates which headers
 * are part of the signing process. Header names must use lowercase characters and must appear in alphabetical order.
 *
 * @internal
 */
export const getSignedHeaders = (headers: HttpRequest['headers']): string =>
	Object.keys(headers)
		.map(key => key.toLowerCase())
		.sort()
		.join(';');