Add examples for flags with Toolbar (#878)

### Description

Adds examples for LauchDarkly, Optimizely, Split, and Statsig to be used
with the Toolbar.

### Demo URL

See all attached Toolbar Flags deployments.

### Type of Change

- [x] New Example
- [ ] Example updates (Bug fixes, new features, etc.)
- [ ] Other (changes to the codebase, but not to examples)

---------

Co-authored-by: Dominik Ferber <[email protected]>

toolbar/toolbar-launchdarkly/.eslintrc.json

@@ -0,0 +1,3 @@
+{
+  "extends": "next/core-web-vitals"
+}

toolbar/toolbar-launchdarkly/.gitignore

@@ -0,0 +1,36 @@
+# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
+
+# dependencies
+/node_modules
+/.pnp
+.pnp.js
+.yarn/install-state.gz
+
+# testing
+/coverage
+
+# next.js
+/.next/
+/out/
+
+# production
+/build
+
+# misc
+.DS_Store
+*.pem
+
+# debug
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# local env files
+.env*.local
+
+# vercel
+.vercel
+
+# typescript
+*.tsbuildinfo
+next-env.d.ts

toolbar/toolbar-launchdarkly/README.md

@@ -0,0 +1,54 @@
+---
+name: Vercel Toolbar x LaunchDarkly example
+slug: toolbar-launchdarkly
+description: Learn how to set up the LaunchDarkly with the Vercel Toolbar
+framework: Next.js
+useCase: Vercel Toolbar
+css: Tailwind
+deployUrl: https://vercel.com/new/clone?repository-url=https://github.com/vercel/examples/tree/main/toolbar/toolbar-launchdarkly&project-name=toolbar-launchdarkly&repository-name=toolbar-launchdarkly&env=LAUNCHDARKLY_API_KEY&env=LAUNCHDARKLY_ENV&env=LAUNCHDARKLY_PROJECT_KEY&env=FLAGS_SECRET
+demoUrl: https://toolbar-launchdarkly.vercel.app
+relatedTemplates:
+  - toolbar-optimizely
+  - toolbar-split
+  - toolbar-statsig
+---
+
+# toolbar-launchdarkly example
+
+This example shows how to combine the Vercel Toolbar with LaunchDarkly in Next.js.
+
+You will need to provide the `LAUNCHDARKLY_API_KEY`, `LAUNCHDARKLY_ENV` and `LAUNCHDARKLY_PROJECT_KEY` environment variables.
+
+You will also need to provide a `FLAGS_SECRET` environment variable. You can generate one with `node -e "console.log(crypto.randomBytes(32).toString('base64url'))"`.
+
+When running locally, you will need to run `vercel link` to link one of your Vercel projects. The environment variables mentioned above need to be defined on the linked project in the Vercel dashboard. Having them in local `.env` files is not enough.
+
+## Demo
+
+https://toolbar-launchdarkly.vercel.app
+
+## How to Use
+
+You can choose from one of the following two methods to use this repository:
+
+### One-Click Deploy
+
+Deploy the example using [Vercel](https://vercel.com?utm_source=github&utm_medium=readme&utm_campaign=vercel-examples):
+
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https://github.com/vercel/examples/tree/main/toolbar/toolbar-launchdarkly&project-name=toolbar-launchdarkly&repository-name=toolbar-launchdarkly&env=LAUNCHDARKLY_API_KEY&env=LAUNCHDARKLY_ENV&env=LAUNCHDARKLY_PROJECT_KEY&env=FLAGS_SECRET)
+
+### Clone and Deploy
+
+Execute [`create-next-app`](https://github.com/vercel/next.js/tree/canary/packages/create-next-app) with [pnpm](https://pnpm.io/installation) to bootstrap the example:
+
+```bash
+pnpm create next-app --example https://github.com/vercel/examples/tree/main/toolbar/toolbar-launchdarkly
+```
+
+Next, run Next.js in development mode:
+
+```bash
+pnpm dev
+```
+
+Deploy it to the cloud with [Vercel](https://vercel.com/new?utm_source=github&utm_medium=readme&utm_campaign=toolbar-launchdarkly) ([Documentation](https://nextjs.org/docs/deployment)).

toolbar/toolbar-launchdarkly/app/.well-known/vercel/flags/route.ts

@@ -0,0 +1,16 @@
+import { getLaunchDarklyData } from '@vercel/flags/providers/launchdarkly'
+import { type NextRequest, NextResponse } from 'next/server'
+import { type ApiData, verifyAccess } from '@vercel/flags'
+
+export async function GET(request: NextRequest) {
+  const access = await verifyAccess(request.headers.get('Authorization'))
+  if (!access) return NextResponse.json(null, { status: 401 })
+
+  const data = await getLaunchDarklyData({
+    apiKey: process.env.LAUNCHDARKLY_API_KEY!,
+    environment: process.env.LAUNCHDARKLY_ENV!,
+    projectKey: process.env.LAUNCHDARKLY_PROJECT_KEY!,
+  })
+
+  return NextResponse.json<ApiData>(data)
+}

toolbar/toolbar-launchdarkly/app/globals.css

@@ -0,0 +1,33 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+:root {
+  --foreground-rgb: 0, 0, 0;
+  --background-start-rgb: 214, 219, 220;
+  --background-end-rgb: 255, 255, 255;
+}
+
+@media (prefers-color-scheme: dark) {
+  :root {
+    --foreground-rgb: 255, 255, 255;
+    --background-start-rgb: 0, 0, 0;
+    --background-end-rgb: 0, 0, 0;
+  }
+}
+
+body {
+  color: rgb(var(--foreground-rgb));
+  background: linear-gradient(
+      to bottom,
+      transparent,
+      rgb(var(--background-end-rgb))
+    )
+    rgb(var(--background-start-rgb));
+}
+
+@layer utilities {
+  .text-balance {
+    text-wrap: balance;
+  }
+}

toolbar/toolbar-launchdarkly/app/launchdarkly.ts

@@ -0,0 +1,16 @@
+import * as LaunchDarkly from '@launchdarkly/node-server-sdk'
+let launchDarklyClient: LaunchDarkly.LDClient
+
+async function initialize() {
+  launchDarklyClient = LaunchDarkly.init(process.env.LAUNCHDARKLY_SDK_KEY!)
+  return launchDarklyClient.waitForInitialization()
+}
+
+export async function getClient(): Promise<LaunchDarkly.LDClient> {
+  if (launchDarklyClient) {
+    await launchDarklyClient.waitForInitialization()
+    return launchDarklyClient
+  }
+  await initialize()
+  return launchDarklyClient
+}

toolbar/toolbar-launchdarkly/app/layout.tsx

@@ -0,0 +1,49 @@
+import type { Metadata } from 'next'
+import { Inter } from 'next/font/google'
+import './globals.css'
+import { VercelToolbar } from '@vercel/toolbar/next'
+import { FlagValues } from '@vercel/flags/react'
+import { Suspense } from 'react'
+import { FlagValuesType, encrypt } from '@vercel/flags'
+
+const inter = Inter({ subsets: ['latin'] })
+
+export const metadata: Metadata = {
+  title: 'Toolbar Flags',
+}
+
+async function ConfidentialFlagValues({
+  flagValues,
+}: {
+  flagValues: FlagValuesType
+}) {
+  const encryptedFlagValues = await encrypt(flagValues)
+  return <FlagValues values={encryptedFlagValues} />
+}
+
+export default function RootLayout({
+  children,
+}: Readonly<{
+  children: React.ReactNode
+}>) {
+  const flags = { instructions: true }
+
+  return (
+    <html lang="en">
+      <body className={inter.className}>
+        {children}
+        {/*
+          ⚠️ This shows the toolbar to all visitors
+
+          See detailed instructions to limit who can see the toolbar for real applications:
+          https://vercel.com/docs/workflow-collaboration/vercel-toolbar/in-production-and-localhost/add-to-production
+        */}
+        <VercelToolbar />
+        {/* Render this tag to tell the application about your flags */}
+        <Suspense fallback={null}>
+          <ConfidentialFlagValues flagValues={flags} />
+        </Suspense>
+      </body>
+    </html>
+  )
+}

toolbar/toolbar-launchdarkly/app/page.tsx

@@ -0,0 +1,181 @@
+import Image from 'next/image'
+import { cookies } from 'next/headers'
+import { Suspense } from 'react'
+import {
+  encrypt,
+  decrypt,
+  type FlagValuesType,
+  type FlagOverridesType,
+} from '@vercel/flags'
+import { FlagValues } from '@vercel/flags/react'
+import { LDContext } from '@launchdarkly/node-server-sdk'
+import { getClient } from './launchdarkly'
+
+/**
+ * A function which respects overrides set by the Toolbar, and returns feature flags.
+ */
+async function getFlags() {
+  const overridesCookieValue = cookies().get('vercel-flag-overrides')?.value
+  const overrides = overridesCookieValue
+    ? await decrypt<FlagOverridesType>(overridesCookieValue)
+    : null
+
+  const client = await getClient()
+  const context: LDContext = { key: 'context-key-123abc' }
+  // const allFlags = client.allFlagsState(context);
+  const flags = {
+    // We fall back to false here, but you could fall back to values of your
+    // flag provider instead
+    docs: overrides?.docs ?? (await client.variation('docs', context, false)),
+    learn:
+      overrides?.learn ?? (await client.variation('learn', context, false)),
+    templates:
+      overrides?.templates ??
+      (await client.variation('templates', context, false)),
+    deploy:
+      overrides?.deploy ?? (await client.variation('deploy', context, false)),
+  }
+  return flags
+}
+
+async function ConfidentialFlagValues({
+  flagValues,
+}: {
+  flagValues: FlagValuesType
+}) {
+  const encryptedFlagValues = await encrypt(flagValues)
+  return <FlagValues values={encryptedFlagValues} />
+}
+
+export default async function Home() {
+  // Note that this top-level await is blocking rendering.
+  // In a real application you could extract the Docs, Learn, Templates, Deploy
+  // components into their own suspense boundaries to allow flushing the main
+  // tag without blocking on the flags.
+  const flags = await getFlags()
+
+  return (
+    <main className="flex min-h-screen flex-col items-center justify-between p-24">
+      <Suspense fallback={null}>
+        <ConfidentialFlagValues flagValues={flags} />
+      </Suspense>
+      <div className="z-10 max-w-5xl w-full items-center justify-between font-mono text-sm lg:flex">
+        <p className="fixed left-0 top-0 flex w-full justify-center border-b border-gray-300 bg-gradient-to-b from-zinc-200 pb-6 pt-8 backdrop-blur-2xl dark:border-neutral-800 dark:bg-zinc-800/30 dark:from-inherit lg:static lg:w-auto  lg:rounded-xl lg:border lg:bg-gray-200 lg:p-4 lg:dark:bg-zinc-800/30">
+          Get started by editing&nbsp;
+          <code className="font-mono font-bold">app/page.tsx</code>
+        </p>
+        <div className="fixed bottom-0 left-0 flex h-48 w-full items-end justify-center bg-gradient-to-t from-white via-white dark:from-black dark:via-black lg:static lg:h-auto lg:w-auto lg:bg-none">
+          <a
+            className="pointer-events-none flex place-items-center gap-2 p-8 lg:pointer-events-auto lg:p-0"
+            href="https://vercel.com?utm_source=create-next-app&utm_medium=appdir-template&utm_campaign=create-next-app"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            By{' '}
+            <Image
+              src="/vercel.svg"
+              alt="Vercel Logo"
+              className="dark:invert"
+              width={100}
+              height={24}
+              priority
+            />
+          </a>
+        </div>
+      </div>
+
+      <div className="relative flex place-items-center before:absolute before:h-[300px] before:w-full sm:before:w-[480px] before:-translate-x-1/2 before:rounded-full before:bg-gradient-radial before:from-white before:to-transparent before:blur-2xl before:content-[''] after:absolute after:-z-20 after:h-[180px] after:w-full sm:after:w-[240px] after:translate-x-1/3 after:bg-gradient-conic after:from-sky-200 after:via-blue-200 after:blur-2xl after:content-[''] before:dark:bg-gradient-to-br before:dark:from-transparent before:dark:to-blue-700 before:dark:opacity-10 after:dark:from-sky-900 after:dark:via-[#0141ff] after:dark:opacity-40 before:lg:h-[360px] z-[-1]">
+        <Image
+          className="relative dark:drop-shadow-[0_0_0.3rem_#ffffff70] dark:invert"
+          src="/next.svg"
+          alt="Next.js Logo"
+          width={180}
+          height={37}
+          priority
+        />
+      </div>
+
+      <div className="mb-32 grid text-center lg:max-w-5xl lg:w-full lg:mb-0 lg:grid-cols-4 lg:text-left">
+        {/* Using a feature flag here to conditionally show or hide the pill */}
+        {flags.docs && (
+          <a
+            href="https://nextjs.org/docs?utm_source=create-next-app&utm_medium=appdir-template&utm_campaign=create-next-app"
+            className="group rounded-lg border border-transparent px-5 py-4 transition-colors hover:border-gray-300 hover:bg-gray-100 hover:dark:border-neutral-700 hover:dark:bg-neutral-800/30"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            <h2 className={`mb-3 text-2xl font-semibold`}>
+              Docs{' '}
+              <span className="inline-block transition-transform group-hover:translate-x-1 motion-reduce:transform-none">
+                -&gt;
+              </span>
+            </h2>
+            <p className={`m-0 max-w-[30ch] text-sm opacity-50`}>
+              Find in-depth information about Next.js features and API.
+            </p>
+          </a>
+        )}
+
+        {/* Using a feature flag here to conditionally show or hide the pill */}
+        {flags.learn && (
+          <a
+            href="https://nextjs.org/learn?utm_source=create-next-app&utm_medium=appdir-template-tw&utm_campaign=create-next-app"
+            className="group rounded-lg border border-transparent px-5 py-4 transition-colors hover:border-gray-300 hover:bg-gray-100 hover:dark:border-neutral-700 hover:dark:bg-neutral-800/30"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            <h2 className={`mb-3 text-2xl font-semibold`}>
+              Learn{' '}
+              <span className="inline-block transition-transform group-hover:translate-x-1 motion-reduce:transform-none">
+                -&gt;
+              </span>
+            </h2>
+            <p className={`m-0 max-w-[30ch] text-sm opacity-50`}>
+              Learn about Next.js in an interactive course with&nbsp;quizzes!
+            </p>
+          </a>
+        )}
+
+        {/* Using a feature flag here to conditionally show or hide the pill */}
+        {flags.templates && (
+          <a
+            href="https://vercel.com/templates?framework=next.js&utm_source=create-next-app&utm_medium=appdir-template&utm_campaign=create-next-app"
+            className="group rounded-lg border border-transparent px-5 py-4 transition-colors hover:border-gray-300 hover:bg-gray-100 hover:dark:border-neutral-700 hover:dark:bg-neutral-800/30"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            <h2 className={`mb-3 text-2xl font-semibold`}>
+              Templates{' '}
+              <span className="inline-block transition-transform group-hover:translate-x-1 motion-reduce:transform-none">
+                -&gt;
+              </span>
+            </h2>
+            <p className={`m-0 max-w-[30ch] text-sm opacity-50`}>
+              Explore starter templates for Next.js.
+            </p>
+          </a>
+        )}
+
+        {/* Using a feature flag here to conditionally show or hide the pill */}
+        {flags.deploy && (
+          <a
+            href="https://vercel.com/new?utm_source=create-next-app&utm_medium=appdir-template&utm_campaign=create-next-app"
+            className="group rounded-lg border border-transparent px-5 py-4 transition-colors hover:border-gray-300 hover:bg-gray-100 hover:dark:border-neutral-700 hover:dark:bg-neutral-800/30"
+            target="_blank"
+            rel="noopener noreferrer"
+          >
+            <h2 className={`mb-3 text-2xl font-semibold`}>
+              Deploy{' '}
+              <span className="inline-block transition-transform group-hover:translate-x-1 motion-reduce:transform-none">
+                -&gt;
+              </span>
+            </h2>
+            <p className={`m-0 max-w-[30ch] text-sm opacity-50 text-balance`}>
+              Instantly deploy your Next.js site to a shareable URL with Vercel.
+            </p>
+          </a>
+        )}
+      </div>
+    </main>
+  )
+}