cloudflare-worker-base

Cloudflare Worker Base Stack

Production-tested: cloudflare-worker-base-test (https://cloudflare-worker-base-test.webfonts.workers.dev) Last Updated: 2025-10-20 Status: Production Ready ✅

Quick Start (5 Minutes)

1. Scaffold Project

npm create cloudflare@latest my-worker -- \
  --type hello-world \
  --ts \
  --git \
  --deploy false \
  --framework none

Why these flags:

• --type hello-world: Clean starting point
• --ts: TypeScript support
• --git: Initialize git repo
• --deploy false: Don't deploy yet (configure first)
• --framework none: We'll add Vite ourselves

2. Install Dependencies

cd my-worker
npm install hono@4.10.1
npm install -D @cloudflare/vite-plugin@1.13.13 vite@latest

Version Notes:

• hono@4.10.1: Latest stable (verified 2025-10-20)
• @cloudflare/vite-plugin@1.13.13: Latest stable, fixes HMR race condition
• vite: Latest version compatible with Cloudflare plugin

3. Configure Wrangler

Create or update wrangler.jsonc:

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "account_id": "YOUR_ACCOUNT_ID",
  "compatibility_date": "2025-10-11",
  "observability": {
    "enabled": true
  },
  "assets": {
    "directory": "./public/",
    "binding": "ASSETS",
    "not_found_handling": "single-page-application",
    "run_worker_first": ["/api/*"]
  }
}

CRITICAL: run_worker_first Configuration

• Without this, SPA fallback intercepts API routes
• API routes return index.html instead of JSON
• Source: workers-sdk #8879

4. Configure Vite

Create vite.config.ts:

import { defineConfig } from 'vite'
import { cloudflare } from '@cloudflare/vite-plugin'

export default defineConfig({
  plugins: [
    cloudflare({
      // Optional: Configure the plugin if needed
    }),
  ],
})

Why @cloudflare/vite-plugin:

• Official plugin from Cloudflare
• Supports HMR with Workers
• Enables local development with Miniflare
• Version 1.13.13 fixes "A hanging Promise was canceled" error

The Four-Step Setup Process

Step 1: Create Hono App with API Routes

Create src/index.ts:

/**
 * Cloudflare Worker with Hono
 *
 * CRITICAL: Export pattern to prevent build errors
 * ✅ CORRECT: export default app
 * ❌ WRONG:   export default { fetch: app.fetch }
 */

import { Hono } from 'hono'

// Type-safe environment bindings
type Bindings = {
  ASSETS: Fetcher
}

const app = new Hono<{ Bindings: Bindings }>()

/**
 * API Routes
 * Handled BEFORE static assets due to run_worker_first config
 */
app.get('/api/hello', (c) => {
  return c.json({
    message: 'Hello from Cloudflare Workers!',
    timestamp: new Date().toISOString(),
  })
})

app.get('/api/health', (c) => {
  return c.json({
    status: 'ok',
    version: '1.0.0',
    environment: c.env ? 'production' : 'development',
  })
})

/**
 * Fallback to Static Assets
 * Any route not matched above is served from public/ directory
 */
app.all('*', (c) => {
  return c.env.ASSETS.fetch(c.req.raw)
})

/**
 * Export the Hono app directly (ES Module format)
 * This is the correct pattern for Cloudflare Workers with Hono + Vite
 */
export default app

Why This Export Pattern:

• Source: honojs/hono #3955
• Using { fetch: app.fetch } causes: "Cannot read properties of undefined (reading 'map')"
• Exception: If you need scheduled/tail handlers, use Module Worker format:

``typescript export default { fetch: app.fetch, scheduled: async (event, env, ctx) => { / ... / } } ``

Step 2: Create Static Frontend

Create public/index.html:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>My Worker App</title>
  <link rel="stylesheet" href="/styles.css">
</head>
<body>
  <div class="container">
    <h1>Cloudflare Worker + Static Assets</h1>
    <button onclick="testAPI()">Test API</button>
    <pre id="output"></pre>
  </div>
  <script src="/script.js"></script>
</body>
</html>

Create public/script.js:

async function testAPI() {
  const response = await fetch('/api/hello')
  const data = await response.json()
  document.getElementById('output').textContent = JSON.stringify(data, null, 2)
}

Create public/styles.css:

body {
  font-family: system-ui, -apple-system, sans-serif;
  max-width: 800px;
  margin: 40px auto;
  padding: 20px;
}

button {
  background: #0070f3;
  color: white;
  border: none;
  padding: 12px 24px;
  border-radius: 6px;
  cursor: pointer;
}

pre {
  background: #f5f5f5;
  padding: 16px;
  border-radius: 6px;
  overflow-x: auto;
}

Step 3: Update Package Scripts

Update package.json:

{
  "scripts": {
    "dev": "wrangler dev",
    "deploy": "wrangler deploy",
    "cf-typegen": "wrangler types"
  }
}

Step 4: Test & Deploy

# Generate TypeScript types for bindings
npm run cf-typegen

# Start local dev server (http://localhost:8787)
npm run dev

# Deploy to production
npm run deploy

Known Issues Prevention

This skill prevents 6 documented issues:

Issue #1: Export Syntax Error

Error: "Cannot read properties of undefined (reading 'map')" Source: honojs/hono #3955 Prevention: Use export default app (NOT { fetch: app.fetch })

Issue #2: Static Assets Routing Conflicts

Error: API routes return index.html instead of JSON Source: workers-sdk #8879 Prevention: Add "run_worker_first": ["/api/*"] to wrangler.jsonc

Issue #3: Scheduled/Cron Not Exported

Error: "Handler does not export a scheduled() function" Source: honojs/vite-plugins #275 Prevention: Use Module Worker format when needed:

export default {
  fetch: app.fetch,
  scheduled: async (event, env, ctx) => { /* ... */ }
}

Issue #4: HMR Race Condition

Error: "A hanging Promise was canceled" during development Source: workers-sdk #9518 Prevention: Use @cloudflare/vite-plugin@1.13.13 or later

Issue #5: Static Assets Upload Race

Error: Non-deterministic deployment failures in CI/CD Source: workers-sdk #7555 Prevention: Use Wrangler 4.x+ with retry logic (fixed in recent versions)

Issue #6: Service Worker Format Confusion

Error: Using deprecated Service Worker format Source: Cloudflare migration guide Prevention: Always use ES Module format (shown in Step 1)

Configuration Files Reference

wrangler.jsonc (Full Example)

{
  "$schema": "node_modules/wrangler/config-schema.json",
  "name": "my-worker",
  "main": "src/index.ts",
  "account_id": "YOUR_ACCOUNT_ID",
  "compatibility_date": "2025-10-11",
  "observability": {
    "enabled": true
  },
  "assets": {
    "directory": "./public/",
    "binding": "ASSETS",
    "not_found_handling": "single-page-application",
    "run_worker_first": ["/api/*"]
  }
  /* Optional: Environment Variables */
  // "vars": { "MY_VARIABLE": "production_value" }

  /* Optional: KV Namespace Bindings */
  // "kv_namespaces": [
  //   { "binding": "MY_KV", "id": "YOUR_KV_ID" }
  // ]

  /* Optional: D1 Database Bindings */
  // "d1_databases": [
  //   { "binding": "DB", "database_name": "my-db", "database_id": "YOUR_DB_ID" }
  // ]

  /* Optional: R2 Bucket Bindings */
  // "r2_buckets": [
  //   { "binding": "MY_BUCKET", "bucket_name": "my-bucket" }
  // ]
}

Why wrangler.jsonc over wrangler.toml:

• JSON format preferred since Wrangler v3.91.0
• Better IDE support with JSON schema
• Com