chore: Add eslint and fix linter issues

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

.eslintrc.json

@@ -0,0 +1,3 @@
+{
+	"extends": ["@nextcloud/eslint-config/typescript"]
+}

jest.config.ts

@@ -0,0 +1,7 @@
+import type { Config } from 'jest'
+
+const config: Config = {
+	testEnvironment: 'jsdom',
+}
+
+export default config

lib/index.ts

@@ -7,13 +7,13 @@ import { onError as onNotLoggedInError } from './interceptors/not-logged-in'
 
 interface CancelableAxiosInstance extends AxiosInstance {
 	CancelToken: CancelTokenStatic
-	isCancel(value: any): boolean
+	isCancel: typeof Axios.isCancel
 }
 
-const client: any = Axios.create({
+const client = Axios.create({
 	headers: {
-		requesttoken: getRequestToken() ?? ''
-	}
+		requesttoken: getRequestToken() ?? '',
+	},
 })
 const cancelableClient: CancelableAxiosInstance = Object.assign(client, {
 	CancelToken: Axios.CancelToken,
@@ -24,6 +24,6 @@ cancelableClient.interceptors.response.use(r => r, onCsrfTokenError(cancelableCl
 cancelableClient.interceptors.response.use(r => r, onMaintenanceModeError(cancelableClient))
 cancelableClient.interceptors.response.use(r => r, onNotLoggedInError)
 
-onRequestTokenUpdate(token => client.defaults.headers.requesttoken = token)
+onRequestTokenUpdate(token => { client.defaults.headers.requesttoken = token })
 
 export default cancelableClient

lib/interceptors/maintenance-mode.ts

@@ -20,8 +20,8 @@ export const onError = axios => async (error) => {
 		&& (!config[RETRY_DELAY_KEY] || config[RETRY_DELAY_KEY] <= 32)) {
 		const retryDelay = (config[RETRY_DELAY_KEY] ?? 1) * 2
 		console.warn(`Request to ${responseURL} failed because of maintenance mode. Retrying in ${retryDelay}s`)
-		await new Promise((resolve, _) => {
-			setTimeout(resolve, retryDelay*1000)
+		await new Promise((resolve) => {
+			setTimeout(resolve, retryDelay * 1000)
 		})
 
 		return axios({