Better error handling

src/services/api/api.service.js

@@ -47,6 +47,7 @@ const MASTODON_USER_FAVORITES_TIMELINE_URL = '/api/v1/favourites'
 import { each, map } from 'lodash'
 import { parseStatus, parseUser, parseNotification } from '../entity_normalizer/entity_normalizer.service.js'
 import 'whatwg-fetch'
+import { StatusCodeError } from '../errors/errors'
 
 const oldfetch = window.fetch
 
@@ -244,13 +245,15 @@ const denyUser = ({id, credentials}) => {
 const fetchUser = ({id, credentials}) => {
   let url = `${USER_URL}?user_id=${id}`
   return fetch(url, { headers: authHeaders(credentials) })
-    .then((data) => {
-      if (!data.ok) {
-        throw Error(data.statusText)
-      }
-      return data
+    .then((response) => {
+      return new Promise((resolve, reject) => response.json()
+        .then((json) => {
+          if (!response.ok) {
+            return reject(new StatusCodeError(response.status, json, { url }, response))
+          }
+          return resolve(json)
+        }))
     })
-    .then((data) => data.json())
     .then((data) => parseUser(data))
 }
 

src/services/errors/errors.js

@@ -0,0 +1,14 @@
+export function StatusCodeError (statusCode, body, options, response) {
+  this.name = 'StatusCodeError'
+  this.statusCode = statusCode
+  this.message = statusCode + ' - ' + (JSON && JSON.stringify ? JSON.stringify(body) : body)
+  this.error = body // legacy attribute
+  this.options = options
+  this.response = response
+
+  if (Error.captureStackTrace) { // required for non-V8 environments
+    Error.captureStackTrace(this)
+  }
+}
+StatusCodeError.prototype = Object.create(Error.prototype)
+StatusCodeError.prototype.constructor = StatusCodeError