ts: Convert csrf module to TypeScript.

static/js/csrf.ts

@@ -1,6 +1,6 @@
 import $ from "jquery";
 
-export let csrf_token;
+export let csrf_token: string | undefined;
 
 $(() => {
     // This requires that we used Jinja2's {% csrf_input %} somewhere on the page.
@@ -11,7 +11,11 @@ $(() => {
     }
 
     $.ajaxSetup({
-        beforeSend(xhr, settings) {
+        beforeSend(xhr: JQuery.jqXHR, settings: JQuery.AjaxSettings) {
+            if (settings.url === undefined || csrf_token === undefined) {
+                throw new Error("settings.url and/or csrf_token are missing.");
+            }
+
             if (!(/^http:.*/.test(settings.url) || /^https:.*/.test(settings.url))) {
                 // Only send the token to relative URLs i.e. locally.
                 xhr.setRequestHeader("X-CSRFToken", csrf_token);

tools/test-js-with-node

@@ -53,7 +53,7 @@ EXEMPT_FILES = {
     "static/js/condense.js",
     "static/js/confirm_dialog.js",
     "static/js/copy_and_paste.js",
-    "static/js/csrf.js",
+    "static/js/csrf.ts",
     "static/js/css_variables.js",
     "static/js/debug.js",
     "static/js/deprecated_feature_notice.js",