export function uploadWithProgress(url, options: RequestInit, onProgress: ((ev: ProgressEvent) => any) | null): Promise { return new Promise((resolve, reject) => { const xhr = new XMLHttpRequest() xhr.onload = () => { if(xhr.status >= 400) { return reject(xhr.responseText) } resolve(xhr.responseText) } xhr.onerror = reject if(onProgress && xhr.upload) { xhr.upload.onprogress = onProgress xhr.upload.onerror = reject } else { console.error("Could not attach progress event listener") } xhr.open(options.method || "GET", url, true) if(options.headers) { for(const key in options.headers) { xhr.setRequestHeader(key, options.headers[key]) } } xhr.send(options.body) }) }