/**
 * Fetches JSON data from a specified URI.
 * URI:s starting with `/rest-api`, `/appresource`, `/edit-app-config` or a protocol, for example
 * `https://` will be left as is. Other URI:s willbe converted to match a route in the current app
 * with `getRouteUri`.
 *
 * @param {string} uri - The URI to fetch JSON data from.
 * @param {object} options - The options for the fetch request, see <https://developer.mozilla.org/en-US/docs/Web/API/fetch#parameters>.
 * @param {string} options.method - The HTTP method to use in the request.
 * @param {object} options.params - The parameters to be included in the request URL.
 * @param {object} options.body - The body to include in the request.
 * @param {number} options.retries - The number of retries to attempt in case of a timeout error.
 * @param {object} options.headers - The headers to be included in the request.
 * @returns {Promise<object>} A promise that resolves to the JSON response.
 * @throws {Error} If the response is not successful or cannot be parsed as JSON.
 */
export default function fetchJson(uri: string, options?: {
    method: string;
    params: object;
    body: object;
    retries: number;
    headers: object;
}): Promise<object>;