Build an in-app feedback form in TanStack Start

src/
  components/feedback-form.tsx
  lib/
    session.ts
    user-middleware.ts
    users.ts
  routes/
    _app.tsx
    _app/projects/$projectId/settings.tsx
  server/
    feedback.ts
    user.ts
.env

IKIFORM_SECRET_KEY=ik_sk_your_secret_key
SESSION_SECRET=at-least-32-characters-from-your-auth-setup

import { createMiddleware } from "@tanstack/react-start";
import { getAppSession } from "./session";
import { findUser } from "./users";

export const userMiddleware = createMiddleware({ type: "function" }).server(async ({ next }) => {
  const session = await getAppSession();
  const user = session.userId ? await findUser(session.userId) : null;
  return next({ context: { user: user ? { id: user.id, email: user.email } : null } });
});

import { createServerFn } from "@tanstack/react-start";
import { getRequestHeader } from "@tanstack/react-start/server";
import { userMiddleware } from "../lib/user-middleware";

export type FeedbackResult = { status: "sent" } | { status: "error"; message: string };

const ROUTE_ID = /^\/[A-Za-z0-9/$_.-]{0,119}$/;

function pageFrom(referer: string | undefined) {
  try {
    const url = new URL(referer ?? "");
    return url.origin + url.pathname;
  } catch {
    return "";
  }
}

export const sendFeedback = createServerFn({ method: "POST" })
  .middleware([userMiddleware])
  .validator((data: unknown) => {
    if (!(data instanceof FormData)) throw new Error("Expected form data");
    const rating = Number(data.get("rating"));
    const screen = String(data.get("screen") ?? "");
    return {
      rating: Number.isInteger(rating) && rating >= 1 && rating <= 5 ? rating : null,
      comment: String(data.get("comment") ?? "").trim().slice(0, 4000),
      screen: ROUTE_ID.test(screen) ? screen : "unknown",
      trap: String(data.get("_gotcha") ?? ""),
    };
  })
  .handler(async ({ data, context }): Promise<FeedbackResult> => {
    if (!context.user) return { status: "error", message: "You're signed out. Sign in and send it again." };
    if (data.rating === null) return { status: "error", message: "Choose a score first." };

    const origin = getRequestHeader("origin");
    let response: Response;
    try {
      response = await fetch("https://ikiform.com/f/frm_xxxxxxxxxxxxxxxx", {
        method: "POST",
        headers: {
          Accept: "application/json",
          "Content-Type": "application/json",
          Authorization: `Bearer ${process.env.IKIFORM_SECRET_KEY}`,
          ...(origin ? { Origin: origin } : {}),
        },
        body: JSON.stringify({
          rating: data.rating,
          comment: data.comment,
          page: pageFrom(getRequestHeader("referer")),
          screen: data.screen,
          user_id: context.user.id,
          email: context.user.email,
          _gotcha: data.trap,
        }),
        signal: AbortSignal.timeout(8000),
      });
    } catch {
      return { status: "error", message: "Feedback is unreachable right now. Try again shortly." };
    }

    const result = await response.json().catch(() => null);
    if (result?.ok) return { status: "sent" };
    return { status: "error", message: result?.error?.message ?? "That didn't go through. Try again." };
  });

import { useMatches } from "@tanstack/react-router";
import { useServerFn } from "@tanstack/react-start";
import { type FormEvent, useState } from "react";
import { type FeedbackResult, sendFeedback } from "../server/feedback";

const SCORES = ["Badly", "Poorly", "Okay", "Well", "Very well"];

export function FeedbackForm() {
  const send = useServerFn(sendFeedback);
  const screen = useMatches({ select: (matches) => matches.at(-1)?.routeId ?? "unknown" });
  const [result, setResult] = useState<FeedbackResult | null>(null);
  const [pending, setPending] = useState(false);

  async function onSubmit(event: FormEvent<HTMLFormElement>) {
    event.preventDefault();
    const data = new FormData(event.currentTarget);
    data.set("screen", screen);
    setPending(true);
    try {
      setResult(await send({ data }));
    } catch {
      setResult({ status: "error", message: "We lost the connection. Try again." });
    } finally {
      setPending(false);
    }
  }

  if (result?.status === "sent") return <p role="status">Thanks. We read every one.</p>;

  return (
    <form method="post" onSubmit={onSubmit} aria-busy={pending}>
      <fieldset>
        <legend>How is this screen working for you?</legend>
        {SCORES.map((label, index) => (
          <label key={label}>
            <input type="radio" name="rating" value={index + 1} required /> {label}
          </label>
        ))}
      </fieldset>
      <label htmlFor="feedback-comment">What would make it better?</label>
      <textarea id="feedback-comment" name="comment" rows={4} maxLength={4000} />
      <input name="_gotcha" type="text" tabIndex={-1} autoComplete="off" hidden />
      {result?.status === "error" ? <p role="alert">{result.message}</p> : null}
      <button disabled={pending}>{pending ? "Sending" : "Send feedback"}</button>
    </form>
  );
}

import { createFileRoute, Outlet, redirect } from "@tanstack/react-router";
import { FeedbackForm } from "../components/feedback-form";
import { getCurrentUserFn } from "../server/user";

export const Route = createFileRoute("/_app")({
  beforeLoad: async () => {
    const user = await getCurrentUserFn();
    if (!user) throw redirect({ to: "/login" });
    return { user };
  },
  component: () => (
    <>
      <Outlet />
      <aside>
        <FeedbackForm />
      </aside>
    </>
  ),
});