Fetch shim for Matrix JS SDK

request.ts

import stringify from './querystring';

// Adjusted from http-api.ts to use fetch.
type RequestCallback = (err?: Error, response?: Response, body?: string) => void;

export default class RequestWrapper {

    static fetchFn: typeof fetch;

    static getRequestFn() {
        let fn = (options, callbackFn: RequestCallback, signal) => {
            RequestWrapper.fetchFn(
                // This is brought over from the SDK's use of request.
                options.uri + '?' + stringify(options.qs, options.qsStringifyOptions),
                {...options, signal}
            ).then(async (response) => {
                callbackFn(null, response, await response.text());
            })
            .catch(err => {
                if (err.name !== 'AbortError') {
                    throw Object.assign(new Error(
                        err?.description || 'Error making request to Matrix API.'
                    ), {raw: err});
                }
            });
        };
        return (options, callback) => {
            const abortController = new AbortController();
            fn.prototype.abort = abortController.abort.bind(abortController);
            return new fn(options, callback, abortController.signal)
        }
    }

}