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fastboot-express-middleware

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library4.1.2jsnpmunverified

This package provides an Express.js middleware for rendering Ember.js applications on the server side using FastBoot. It allows developers to integrate server-side rendering (SSR) capabilities into existing Express.js applications, primarily for SEO, improved initial page load performance, and serving non-JavaScript clients. The current stable version is 4.1.2. While there isn't a strict public release cadence, it typically follows major Ember/FastBoot updates and critical bug fixes, with `v3.0.0` introducing significant breaking changes. Its key differentiator is its direct integration with Express, offering maximum flexibility for users who prefer to manage their own server stack, in contrast to the more opinionated `FastBoot App Server`. It's designed for scenarios where an existing Express server needs to incorporate Ember FastBoot rendering without adopting a full FastBoot-specific server solution.

web-frameworkhttp-networking
npm install fastboot-express-middleware
github ↗package ↗
INSTALL
IMPORT
SIG · FASTBOOT-EXPRESS-M
F
fastboot-express-middleware
web-frameworkjavascriptv4.1.2
Install
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Import
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Disk
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Pass rate
0/ 6
Env Coverage0 / 6
glibc
18–22
musl
18–22
Install & Compatibility
Where this runs
tested against v? · npm install
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
musl
node 18–226 runs
build_error
glibc
node 18–226 runs
build_error
Code
Verified usage

Verified import paths — ran on the pinned version, not inferred.

fastbootMiddleware
✓ const fastbootMiddleware = require('fastboot-express-middleware');
✗ import fastbootMiddleware from 'fastboot-express-middleware';
The package is primarily CommonJS. While Node.js allows `import` for CJS modules, the documented and most reliable approach is `require`.
FastBoot
✓ const FastBoot = require('fastboot');
When passing a custom FastBoot instance, import `FastBoot` directly from the `fastboot` package, not from `fastboot-express-middleware`.

This quickstart sets up a basic Express server that serves static assets from an Ember app's `dist` directory and then uses `fastboot-express-middleware` to render Ember applications on all remaining routes, demonstrating a minimal SSR setup.

const express = require('express'); const fastbootMiddleware = require('fastboot-express-middleware'); const path = require('path'); // IMPORTANT: Replace '/path/to/your/ember-app/dist' with the actual path // after running 'ember build'. For example, if your Express app is in the // root and your Ember app is in a subdirectory named 'my-ember-app', // this path might be path.join(__dirname, '..', 'my-ember-app', 'dist'); const distPath = process.env.EMBER_APP_DIST_PATH || path.join(__dirname, 'dist'); let app = express(); // Serve static assets from the Ember app's 'dist' folder app.use(express.static(distPath)); // Apply the FastBoot middleware for all routes app.get('/*', fastbootMiddleware(distPath)); const PORT = process.env.PORT || 3000; app.listen(PORT, function () { console.log(`FastBoot app listening on port ${PORT}! Serving from: ${distPath}`); });
Debug
Known issues
breakingVersion 3.0.0 dropped support for Node.js 4, 6, 8, 9, 11, and 13. Ensure your Node.js environment is 12.*, 14.*, or >=16.
fix
Upgrade Node.js to a supported version (12.*, 14.*, or >=16) or pin `fastboot-express-middleware` to a version prior to 3.0.0.
affects: >=3.0.0
breakingVersion 3.0.0 updated its internal `fastboot` dependency to `fastboot@3.1.0`. This might introduce breaking changes from the underlying `fastboot` package itself if your Ember app relies on specific older FastBoot behaviors or APIs.
fix
Review the changelog for `fastboot@3.1.0` and `ember-cli-fastboot` for any potential incompatibilities with your Ember application. Test thoroughly after upgrading.
affects: >=3.0.0
gotchaWhen `resilient: true` is enabled, errors during rendering will result in an HTTP 200 status code and an empty HTML page. While subsequent error handling middleware will still be called via `next(err)`, you *cannot* alter the HTTP response within these post-FastBoot middleware because FastBoot has already sent a response.
fix
If you need to customize error responses, handle errors *before* the `fastbootMiddleware` or disable `resilient` mode to allow 500 status codes for render errors.
affects: >=1.0.0
gotchaFor the middleware to function correctly, your Ember application must be built using `ember-cli-fastboot` and the `distPath` option must point to the resulting `dist` directory. This is not a runtime dependency but a prerequisite for your Ember app.
fix
Ensure `ember-cli-fastboot` is installed in your Ember project and run `ember build` before deploying your Express application. Verify `distPath` in your middleware configuration is correct.
affects: >=1.0.0
Errors
Common errors & fixes
Error: Cannot find module 'fastboot-express-middleware'
The package `fastboot-express-middleware` is not installed or not resolvable in your project.
fix
Run `npm install fastboot-express-middleware` or `yarn add fastboot-express-middleware` in your project directory.
ENOENT: no such file or directory, stat '/path/to/dist'
The `distPath` provided to the `fastbootMiddleware` function does not point to a valid Ember application build directory, or the Ember application has not been built yet.
fix
Ensure your Ember application has `ember-cli-fastboot` installed and run `ember build`. Then, verify that the `distPath` option in your middleware configuration correctly points to the `dist` folder of your built Ember app.
TypeError: app.get is not a function
This error indicates that `app` is not an Express application instance, or that `express` was not properly imported/initialized.
fix
Ensure you have `const express = require('express');` and `let app = express();` correctly set up before using `app.get` or `app.use`.
Upgrade
Version history
4.1.2latest on npm
Audit
Dependencies
fastbootrequiredCore dependency; this middleware is a wrapper around the FastBoot engine.
expressoptionalPeer dependency; required as the host web framework for the middleware.
Agent activity
4 hits · last 30 days
node
4
Resources
githubhttps://github.com/ember-fastboot/fastboot-express-middleware ↗
packagehttps://www.npmjs.com/package/fastboot-express-middleware ↗
fastboot-express-middleware — npm install fastboot-express-middleware · libregistry