remix-run · pcattori · Feb 22, 2023 · Jan 25, 2023 · Jan 25, 2023 · Jan 25, 2023
diff --git a/.changeset/hmr.md b/.changeset/hmr.md
@@ -0,0 +1,20 @@
+---
+"@remix-run/dev": minor
+"@remix-run/react": minor
+"@remix-run/server-runtime": minor
+---
+
+Hot Module Replacement and Hot Data Revalidation
+
+- Requires `unstable_dev` future flag to be enabled
+- HMR provided through React Refresh
+
+Features:
+- HMR for component and style changes
+- HDR when loaders for current route change
+
+Known limitations for MVP:
+- Only implemented for React via React Refresh
+- No `import.meta.hot` API exposed yet
+- Revalidates _all_ loaders on route when loader changes are detected
+- Loader changes do not account for imported dependencies changing
diff --git a/integration/hmr-test.ts b/integration/hmr-test.ts
@@ -0,0 +1,363 @@
+import { test, expect } from "@playwright/test";
+import execa from "execa";
+import fs from "node:fs";
+import path from "node:path";
+import type { Readable } from "node:stream";
+import getPort, { makeRange } from "get-port";
+
+import { createFixtureProject } from "./helpers/create-fixture";
+
+let fixture = (options: { port: number; appServerPort: number }) => ({
+  future: {
+    unstable_dev: {
+      port: options.port,
+      appServerPort: options.appServerPort,
+    },
+    unstable_tailwind: true,
+  },
+  files: {
+    "package.json": `
+        {
+          "private": true,
+          "sideEffects": false,
+          "scripts": {
+            "dev:remix": "cross-env NODE_ENV=development node ./node_modules/@remix-run/dev/dist/cli.js dev",
+            "dev:app": "cross-env NODE_ENV=development nodemon --watch build/ ./server.js"
+          },
+          "dependencies": {
+            "@remix-run/node": "0.0.0-local-version",
+            "@remix-run/react": "0.0.0-local-version",
+            "cross-env": "0.0.0-local-version",
+            "express": "0.0.0-local-version",
+            "isbot": "0.0.0-local-version",
+            "nodemon": "0.0.0-local-version",
+            "react": "0.0.0-local-version",
+            "react-dom": "0.0.0-local-version",
+            "tailwindcss": "0.0.0-local-version"
+          },
+          "devDependencies": {
+            "@remix-run/dev": "0.0.0-local-version",
+            "@types/react": "0.0.0-local-version",
+            "@types/react-dom": "0.0.0-local-version",
+            "typescript": "0.0.0-local-version"
+          },
+          "engines": {
+            "node": ">=14"
+          }
+        }
+      `,
+    "server.js": `
+        let path = require("path");
+        let express = require("express");
+        let { createRequestHandler } = require("@remix-run/express");
+
+        const app = express();
+        app.use(express.static("public", { immutable: true, maxAge: "1y" }));
+
+        const MODE = process.env.NODE_ENV;
+        const BUILD_DIR = path.join(process.cwd(), "build");
+
+        app.all(
+          "*",
+          createRequestHandler({
+            build: require(BUILD_DIR),
+            mode: MODE,
+          })
+        );
+
+        let port = ${options.appServerPort};
+        app.listen(port, () => {
+          require(BUILD_DIR);
+          console.log('✅ app ready: http://localhost:' + port);
+        });
+      `,
+    "tailwind.config.js": `
+        /** @type {import('tailwindcss').Config} */
+        module.exports = {
+          content: ["./app/**/*.{ts,tsx,jsx,js}"],
+          theme: {
+            extend: {},
+          },
+          plugins: [],
+        };
+      `,
+    "app/tailwind.css": `
+        @tailwind base;
+        @tailwind components;
+        @tailwind utilities;
+      `,
+    "app/root.tsx": `
+        import type { LinksFunction } from "@remix-run/node";
+        import { Link, Links, LiveReload, Meta, Outlet, Scripts } from "@remix-run/react";
+
+        import Counter from "./components/counter";
+        import styles from "./tailwind.css";
+
+        export const links: LinksFunction = () => [
+          { rel: "stylesheet", href: styles },
+        ];
+
+        export default function Root() {
+          return (
+            <html lang="en" className="h-full">
+              <head>
+                <Meta />
+                <Links />
+              </head>
+              <body className="h-full">
+                <header>
+                  <label htmlFor="root-input">Root Input</label>
+                  <input id="root-input" />
+                  <Counter id="root-counter" />
+                  <nav>
+                    <ul>
+                      <li><Link to="/">Home</Link></li>
+                      <li><Link to="/about">About</Link></li>
+                    </ul>
+                  </nav>
+                </header>
+                <Outlet />
+                <Scripts />
+                <LiveReload />
+              </body>
+            </html>
+          );
+        }
+      `,
+    "app/routes/index.tsx": `
+        import { useLoaderData } from "@remix-run/react";
+        export default function Index() {
+          const t = useLoaderData();
+          return (
+            <main>
+              <h1>Index Title</h1>
+            </main>
+          )
+        }
+      `,
+    "app/routes/about.tsx": `
+        import Counter from "../components/counter";
+        export default function About() {
+          return (
+            <main>
+              <h1>About Title</h1>
+              <Counter id="about-counter" />
+            </main>
+          )
+        }
+      `,
+    "app/components/counter.tsx": `
+        import * as React from "react";
+        export default function Counter({ id }) {
+          let [count, setCount] = React.useState(0);
+          return (
+            <p>
+              <button id={id} onClick={() => setCount(count + 1)}>inc {count}</button>
+            </p>
+          );
+        }
+      `,
+  },
+});
+
+let sleep = (ms: number) => new Promise((resolve) => setTimeout(resolve, ms));
+
+let wait = async (
+  callback: () => boolean,
+  { timeoutMs = 1000, intervalMs = 250 } = {}
+) => {
+  let start = Date.now();
+  while (Date.now() - start <= timeoutMs) {
+    if (callback()) {
+      return;
+    }
+    await sleep(intervalMs);
+  }
+  throw Error(`wait: timeout ${timeoutMs}ms`);
+};
+
+let bufferize = (stream: Readable): (() => string) => {
+  let buffer = "";
+  stream.on("data", (data) => (buffer += data.toString()));
+  return () => buffer;
+};
+
+test("HMR", async ({ page }) => {
+  // uncomment for debugging
+  // page.on("console", (msg) => console.log(msg.text()));
+  page.on("pageerror", (err) => console.log(err.message));
+
+  let appServerPort = await getPort({ port: makeRange(3080, 3089) });
+  let port = await getPort({ port: makeRange(3090, 3099) });
+  let projectDir = await createFixtureProject(fixture({ port, appServerPort }));
+
+  // spin up dev server
+  let dev = execa("npm", ["run", "dev:remix"], { cwd: projectDir });
+  let devStdout = bufferize(dev.stdout!);
+  let devStderr = bufferize(dev.stderr!);
+  await wait(
+    () => {
+      let stderr = devStderr();
+      if (stderr.length > 0) throw Error(stderr);
+      return /💿 Built in /.test(devStdout());
+    },
+    { timeoutMs: 10_000 }
+  );
+
+  // spin up app server
+  let app = execa("npm", ["run", "dev:app"], { cwd: projectDir });
+  let appStdout = bufferize(app.stdout!);
+  let appStderr = bufferize(app.stderr!);
+  await wait(
+    () => {
+      let stderr = appStderr();
+      if (stderr.length > 0) throw Error(stderr);
+      return /✅ app ready: /.test(appStdout());
+    },
+    {
+      timeoutMs: 10_000,
+    }
+  );
+
+  try {
+    await page.goto(`http://localhost:${appServerPort}`, {
+      waitUntil: "networkidle",
+    });
+
+    // `<input />` value as page state that
+    // would be wiped out by a full page refresh
+    // but should be persisted by hmr
+    let input = page.getByLabel("Root Input");
+    expect(input).toBeVisible();
+    await input.type("asdfasdf");
+
+    let counter = await page.waitForSelector("#root-counter");
+    await counter.click();
+    await page.waitForSelector(`#root-counter:has-text("inc 1")`);
+
+    let indexPath = path.join(projectDir, "app", "routes", "index.tsx");
+    let originalIndex = fs.readFileSync(indexPath, "utf8");
+    let counterPath = path.join(projectDir, "app", "components", "counter.tsx");
+    let originalCounter = fs.readFileSync(counterPath, "utf8");
+
+    // make content and style changed to index route
+    let newIndex = `
+      import { useLoaderData } from "@remix-run/react";
+      export default function Index() {
+        const t = useLoaderData();
+        return (
+          <main>
+            <h1 className="text-white bg-black">Changed</h1>
+          </main>
+        )
+      }
+    `;
+    fs.writeFileSync(indexPath, newIndex);
+
+    // detect HMR'd content and style changes
+    await page.waitForLoadState("networkidle");
+    let h1 = page.getByText("Changed");
+    await h1.waitFor({ timeout: 2000 });
+    expect(h1).toHaveCSS("color", "rgb(255, 255, 255)");
+    expect(h1).toHaveCSS("background-color", "rgb(0, 0, 0)");
+
+    // verify that `<input />` value was persisted (i.e. hmr, not full page refresh)
+    expect(await page.getByLabel("Root Input").inputValue()).toBe("asdfasdf");
+    await page.waitForSelector(`#root-counter:has-text("inc 1")`);
+
+    // undo change
+    fs.writeFileSync(indexPath, originalIndex);
+    await page.getByText("Index Title").waitFor({ timeout: 2000 });
+    expect(await page.getByLabel("Root Input").inputValue()).toBe("asdfasdf");
+    await page.waitForSelector(`#root-counter:has-text("inc 1")`);
+
+    // add loader
+    let withLoader1 = `
+      import { json } from "@remix-run/node";
+      import { useLoaderData } from "@remix-run/react";
+
+      export let loader = () => json({ hello: "world" })
+
+      export default function Index() {
+        let { hello } = useLoaderData<typeof loader>();
+        return (
+          <main>
+            <h1>Hello, {hello}</h1>
+          </main>
+        )
+      }
+    `;
+    fs.writeFileSync(indexPath, withLoader1);
+    await page.getByText("Hello, world").waitFor({ timeout: 2000 });
+    expect(await page.getByLabel("Root Input").inputValue()).toBe("asdfasdf");
+    await page.waitForSelector(`#root-counter:has-text("inc 1")`);
+
+    let withLoader2 = `
+      import { json } from "@remix-run/node";
+      import { useLoaderData } from "@remix-run/react";
+
+      export function loader() {
+        return json({ hello: "planet" })
+      }
+
+      export default function Index() {
+        let { hello } = useLoaderData<typeof loader>();
+        return (
+          <main>
+            <h1>Hello, {hello}</h1>
+          </main>
+        )
+      }
+    `;
+    fs.writeFileSync(indexPath, withLoader2);
+    await page.getByText("Hello, planet").waitFor({ timeout: 2000 });
+    expect(await page.getByLabel("Root Input").inputValue()).toBe("asdfasdf");
+    await page.waitForSelector(`#root-counter:has-text("inc 1")`);
+
+    // change shared component
+    let updatedCounter = `
+      import * as React from "react";
+      export default function Counter({ id }) {
+        let [count, setCount] = React.useState(0);
+        return (
+          <p>
+            <button id={id} onClick={() => setCount(count - 1)}>dec {count}</button>
+          </p>
+        );
+      }
+    `;
+    fs.writeFileSync(counterPath, updatedCounter);
+    await page.waitForSelector(`#root-counter:has-text("dec 1")`);
+    counter = await page.waitForSelector("#root-counter");
+    await counter.click();
+    await counter.click();
+    await page.waitForSelector(`#root-counter:has-text("dec -1")`);
+
+    await page.click(`a[href="/about"]`);
+    let aboutCounter = await page.waitForSelector(
+      `#about-counter:has-text("dec 0")`
+    );
+    await aboutCounter.click();
+    await page.waitForSelector(`#about-counter:has-text("dec -1")`);
+
+    // undo change
+    fs.writeFileSync(counterPath, originalCounter);
+
+    counter = await page.waitForSelector(`#root-counter:has-text("inc -1")`);
+    await counter.click();
+    counter = await page.waitForSelector(`#root-counter:has-text("inc 0")`);
+
+    aboutCounter = await page.waitForSelector(
+      `#about-counter:has-text("inc -1")`
+    );
+    await aboutCounter.click();
+    aboutCounter = await page.waitForSelector(
+      `#about-counter:has-text("inc 0")`
+    );
+  } finally {
+    dev.kill();
+    app.kill();
+    console.log(devStderr());
+    console.log(appStderr());
+  }
+});