Add lint rule for unhandled promise rejections

ui/app.ts

@@ -71,7 +71,7 @@ let fulfillTimeout = null;
 function fulfill(): void {
   clearTimeout(fulfillTimeout);
   fulfillTimeout = setTimeout(() => {
-    store.fulfill(lastRenderTimestamp, pageVisitTimestamp).then((updated) => {
+    store.fulfill(lastRenderTimestamp, pageVisitTimestamp, (updated) => {
       if (updated) m.redraw();
     });
   }, 100);

ui/components/ping.ts

@@ -27,23 +27,28 @@ const component: ClosureComponent = (vn): Component => {
   let interval: ReturnType<typeof setInterval>;
   let host: string;
 
-  const refresh = async (): Promise<void> => {
-    let status = "";
-    if (host) {
-      try {
-        const res = await store.ping(host);
-        if (res["avg"] != null) status = `${Math.trunc(res["avg"])} ms`;
-        else status = "Unreachable";
-      } catch (err) {
-        setTimeout(() => {
-          throw err;
-        }, 0);
-      }
+  const refresh = (): void => {
+    if (!host) {
+      const dom = (vn as VnodeDOM).dom;
+      if (dom) dom.innerHTML = "";
+      return;
     }
 
-    const dom = (vn as VnodeDOM).dom;
-
-    if (dom) dom.innerHTML = `Pinging ${host}: ${status}`;
+    let status = "";
+    store
+      .ping(host)
+      .then((res) => {
+        if (res["avg"] != null) status = `${Math.trunc(res["avg"])} ms`;
+        else status = "Unreachable";
+      })
+      .catch(() => {
+        status = "Error!";
+        clearInterval(interval);
+      })
+      .finally(() => {
+        const dom = (vn as VnodeDOM).dom;
+        if (dom) dom.innerHTML = `Pinging ${host}: ${status}`;
+      });
   };
 
   return {

ui/components/summon-button.ts

@@ -79,6 +79,9 @@ const component: ClosureComponent = (): Component => {
               .then(() => {
                 e.target.disabled = false;
                 store.fulfill(0, Date.now());
+              })
+              .catch((err) => {
+                throw err;
               });
           },
         },

ui/drawer-component.ts

@@ -441,6 +441,9 @@ const component: ClosureComponent = (): Component => {
                   )
                   .then(() => {
                     store.fulfill(0, Date.now());
+                  })
+                  .catch((err) => {
+                    throw err;
                   });
               },
             },

ui/store.ts

@@ -152,6 +152,8 @@ function checkConnection(): void {
         }
       }
     },
+  }).catch((err) => {
+    notifications.push("error", err.message);
   });
 }
 
@@ -169,11 +171,25 @@ export async function xhrRequest(
   ): any => {
     if (typeof extract === "function") return extract(xhr, _options);
 
+    // https://mithril.js.org/request.html#error-handling
+    if (xhr.status !== 304 && Math.floor(xhr.status / 100) !== 2) {
+      const err = new Error();
+      err["message"] =
+        xhr.status === 0
+          ? "Server is unrachable"
+          : `Unexpected response status code ${xhr.status}`;
+      err["code"] = xhr.status;
+      err["response"] = xhr.responseText;
+      throw err;
+    }
+
     let response: any;
     if (typeof deserialize === "function") {
       response = deserialize(xhr.responseText);
     } else if (
-      xhr.getResponseHeader("content-type").startsWith("application/json")
+      (xhr.getResponseHeader("content-type") || "").startsWith(
+        "application/json"
+      )
     ) {
       try {
         response = xhr.responseText ? JSON.parse(xhr.responseText) : null;
@@ -184,15 +200,6 @@ export async function xhrRequest(
       response = xhr.responseText;
     }
 
-    // https://mithril.js.org/request.html#error-handling
-    if (xhr.status !== 304 && Math.floor(xhr.status / 100) !== 2) {
-      const err = new Error();
-      err["message"] = xhr.responseText;
-      err["code"] = xhr.status;
-      err["response"] = response;
-      throw err;
-    }
-
     return response;
   };
 
@@ -340,7 +347,7 @@ export function fetch(
   return queryResponse;
 }
 
-export function fulfill(
+function _fulfill(
   accessTimestamp: number,
   _fulfillTimestamp: number
 ): Promise<boolean> {
@@ -377,7 +384,16 @@ export function fulfill(
                 m.buildQueryString({
                   filter: memoizedStringify(filter),
                 }),
-              extract: (xhr) => +xhr.getResponseHeader("x-total-count"),
+              extract: (xhr) => {
+                if (!xhr.status) {
+                  throw new Error("Server is unrachable");
+                } else if (xhr.status !== 200) {
+                  throw new Error(
+                    `Unexpected response status code ${xhr.status}`
+                  );
+                }
+                return +xhr.getResponseHeader("x-total-count");
+              },
               background: true,
             })
               .then((c) => {
@@ -560,6 +576,17 @@ export function fulfill(
   });
 }
 
+export function fulfill(
+  accessTimestamp: number,
+  _fulfillTimestamp: number,
+  callback?: (updated: boolean) => void
+): void {
+  _fulfill(accessTimestamp, _fulfillTimestamp).then(callback, (err) => {
+    notifications.push("error", err.message);
+    if (callback) callback(false);
+  });
+}
+
 export function getTimestamp(): number {
   return fulfillTimestamp;
 }
@@ -647,7 +674,12 @@ export function resourceExists(resource: string, id: string): Promise<number> {
       m.buildQueryString({
         filter: memoizedStringify(filter),
       }),
-    extract: (xhr) => +xhr.getResponseHeader("x-total-count"),
+    extract: (xhr) => {
+      if (!xhr.status) throw new Error("Server is unrachable");
+      else if (xhr.status !== 200)
+        throw new Error(`Unexpected response status code ${xhr.status}`);
+      return +xhr.getResponseHeader("x-total-count");
+    },
     background: true,
   });
 }

ui/wizard-page.ts

@@ -87,16 +87,24 @@ export const component: ClosureComponent = (vnode): Component => {
               })
                 .then(() => {
                   setTimeout(() => {
-                    m.request({ url: "init" }).then((o) => {
-                      e.target.disabled = false;
-                      options = o;
-                      notifications.push("success", "Initialization complete", {
-                        "Open Sesame!": () => {
-                          m.route.set("/login");
-                          window.location.reload();
-                        },
+                    m.request({ url: "init" })
+                      .then((o) => {
+                        e.target.disabled = false;
+                        options = o;
+                        notifications.push(
+                          "success",
+                          "Initialization complete",
+                          {
+                            "Open Sesame!": () => {
+                              m.route.set("/login");
+                              window.location.reload();
+                            },
+                          }
+                        );
+                      })
+                      .catch((err) => {
+                        notifications.push("error", err.message);
                       });
-                    });
                   }, 3000);
                   if (opts["users"]) {
                     alert(