setup: Move 401 error check to channel.

Channel already handles all the requests and general errors related to
them; so, channels seems the right place for this check.

static/js/channel.js

@@ -1,7 +1,9 @@
 import $ from "jquery";
 
 import * as blueslip from "./blueslip";
+import {page_params} from "./page_params";
 import * as reload_state from "./reload_state";
+import * as setup from "./setup";
 
 const pending_requests = [];
 
@@ -52,7 +54,28 @@ function call(args, idempotent) {
             return;
         }
 
-        if (xhr.status === 403) {
+        if (xhr.status === 401) {
+            if (
+                setup.password_change_in_progress ||
+                setup.xhr_password_changes.get(xhr) !== setup.password_changes
+            ) {
+                // The backend for handling password change API requests
+                // will replace the user's session; this results in a
+                // brief race where any API request will fail with a 401
+                // error after the old session is deactivated but before
+                // the new one has been propagated to the browser.  So we
+                // skip our normal HTTP 401 error handling if we're in the
+                // process of executing a password change.
+                return;
+            }
+
+            // We got logged out somehow, perhaps from another window
+            // changing the user's password, or a session timeout.  We
+            // could display an error message, but jumping right to
+            // the login page conveys the same information with a
+            // smoother relogin experience.
+            window.location.replace(page_params.login_page);
+        } else if (xhr.status === 403) {
             try {
                 if (
                     JSON.parse(xhr.responseText).code === "CSRF_FAILED" &&

static/js/setup.js

@@ -8,7 +8,7 @@ import * as util from "./util";
 // Miscellaneous early setup.
 export let password_change_in_progress = false;
 export let password_changes = 0;
-const xhr_password_changes = new WeakMap();
+export const xhr_password_changes = new WeakMap();
 
 export function set_password_change_in_progress(value) {
     password_change_in_progress = value;
@@ -55,29 +55,6 @@ $(() => {
         xhr_password_changes.set(xhr, password_changes);
     });
 
-    // For some reason, jQuery wants this to be attached to an element.
-    $(document).ajaxError((event, xhr) => {
-        if (password_change_in_progress || xhr_password_changes.get(xhr) !== password_changes) {
-            // The backend for handling password change API requests
-            // will replace the user's session; this results in a
-            // brief race where any API request will fail with a 401
-            // error after the old session is deactivated but before
-            // the new one has been propagated to the browser.  So we
-            // skip our normal HTTP 401 error handling if we're in the
-            // process of executing a password change.
-            return;
-        }
-
-        if (xhr.status === 401) {
-            // We got logged out somehow, perhaps from another window
-            // changing the user's password, or a session timeout.  We
-            // could display an error message, but jumping right to
-            // the login page conveys the same information with a
-            // smoother re-login experience.
-            window.location.replace(page_params.login_page);
-        }
-    });
-
     $.fn.expectOne = function () {
         if (blueslip && this.length !== 1) {
             blueslip.error("Expected one element in jQuery set, " + this.length + " found");

tools/test-js-with-node

@@ -45,6 +45,7 @@ EXEMPT_FILES = {
     "static/js/billing/upgrade.js",
     "static/js/blueslip.ts",
     "static/js/blueslip_stacktrace.ts",
+    "static/js/channel.js",
     "static/js/click_handlers.js",
     "static/js/compose_actions.js",
     "static/js/compose_closed_ui.js",