When double-clicking on a file, the behavior is:

First click: open the viewer
Second click: close the viewer

But the second click does not correctly close the Viewer, as the method used to cancel the requests does not work.

This PR use modern API to cancel the requests. The requests are now correctly aborted, and the `openFile` method exit because the request call throws an exception.

Fix #893

https://axios-http.com/docs/cancellation
https://developer.mozilla.org/en-US/docs/Web/API/AbortController

Signed-off-by: Louis Chemineau <louis@chmn.me>

src/utils/CancelableRequest.js

@@ -21,36 +21,30 @@
  *
  */
 
-import axios from '@nextcloud/axios'
-
 /**
  * Creates a cancelable axios 'request object'.
  *
  * @param {Function} request the axios promise request
  * @return {object}
  */
-const CancelableRequest = function(request) {
-	/**
-	 * Generate an axios cancel token
-	 */
-	const CancelToken = axios.CancelToken
-	const source = CancelToken.source()
+const CancelableRequest = function (request) {
+	const controller = new AbortController()
 
 	/**
 	 * Execute the request
 	 *
 	 * @param {string} url the url to send the request to
 	 * @param {object} [options] optional config for the request
 	 */
-	const fetch = async function(url, options) {
+	const fetch = async function (url, options) {
 		return request(
 			url,
-			Object.assign({ cancelToken: source.token }, { options })
+			{ ...options, signal: controller.signal }
 		)
 	}
 	return {
 		request: fetch,
-		cancel: source.cancel,
+		cancel: () => controller.abort(),
 	}
 }