felt

library0.2jsnpmunverified

Felt is an on-demand bundler designed for modern JavaScript (ES6 and beyond, typically transpiled via Buble/Rollup) and CSS (CSS Next), serving primarily as a development middleware or a static asset exporter. Currently at version 0.3.2, it requires Node.js 6 or above to run. The package offers three main modes of operation: a standalone CLI web server for quick local development, an Express.js middleware for integration into existing Node.js applications, and a static file exporter for pre-compiling assets for deployment. Its core functionality is highly extensible through 'recipes' and a plugin architecture, exemplified by modules like `felt-rollup`, which allows developers to define custom handler logic for different file types. This on-demand compilation approach is a key differentiator, focusing on speed during development rather than exhaustive pre-bundling.

web-framework devops

npm install felt

github ↗package ↗

INSTALL

IMPORT

SIG · FELT

felt

web-frameworkjavascriptv0.2

Install

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Import

—

Disk

—

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.

felt

✓ const felt = require('felt')

✗ import felt from 'felt'

Felt is a CommonJS module, primarily used with `require()`. There is no native ESM support.

recipe

✓ const recipe = require('felt-recipe-minimal')

✗ import recipe from 'felt-recipe-minimal'

Recipes like `felt-recipe-minimal` are separate CommonJS modules that `felt` consumes. Do not use ES module `import` syntax.

feltConfig

✓ const config = require('./felt.config.js')

✗ import config from './felt.config.js'

Configuration files are expected to be CommonJS modules exporting an object, typically required relative to the application's entry point.

Integrates Felt as an on-demand ES6/CSS bundler middleware with an Express.js server.

const express = require('express'); const felt = require('felt'); const path = require('path'); const config = require('./felt.config.js'); // Assuming felt.config.js exists and exports a Felt config object const app = express(); // Integrate Felt as an on-demand bundling middleware app.use(felt(config)); // Serve static files from the 'public' directory app.use(express.static(path.join(__dirname, 'public'))); const PORT = process.env.PORT ?? 3000; app.listen(PORT, () => { console.log(`Felt server running at http://localhost:${PORT}`); console.log('Serving static files from ./public and bundling JavaScript/CSS on-demand.'); }); // To set up: // 1. npm install express felt felt-rollup rollup-plugin-buble rollup-plugin-node-resolve rollup-plugin-commonjs // 2. Create 'felt.config.js' (as shown in the README example) // 3. Create 'public/index.html' and 'public/main.js' (e.g., 'console.log("Hello from Felt!")') // 4. Run with 'node server.js'

felt --version

Debug

Known issues

breakingFelt is a CommonJS-only package. Attempting to use `import` statements directly in an ES module environment will result in runtime errors. It predates widespread native ESM support in Node.js.

fix

Ensure your project or file where Felt is used operates in a CommonJS context (e.g., by using `.cjs` extension or `"type": "commonjs"` in package.json) and use `require()` syntax. If ESM is required, consider a CJS-to-ESM wrapper or alternative tooling.

affects: >=0.3.0

gotchaFelt itself does not bundle files out of the box; it requires 'recipes' (like `felt-recipe-minimal`) or custom `handlers` specified in its configuration to define how different file types (e.g., `.js`, `.css`) are processed.

fix

Always install a recipe (e.g., `npm install felt-recipe-minimal`) or define custom handlers in your `felt.config.js` file, ensuring all necessary bundler plugins (e.g., `felt-rollup`, `rollup-plugin-buble`) are also installed.

affects: >=0.3.0

gotchaFelt explicitly requires Node.js 6.x or above. While it may run on newer versions, its older dependencies (e.g., Rollup 0.x, Buble) might lead to compatibility issues or missing features compared to modern bundling setups.

fix

Ensure your Node.js environment is at least version 6.x. For newer Node.js versions, test thoroughly and be prepared for potential dependency conflicts or deprecation warnings related to older build tools.

affects: <6.0.0

gotchaFelt's 'on-demand' bundling means assets are compiled dynamically upon request. This is great for development hot-reloading but can introduce latency for initial requests or heavy load in production environments compared to pre-compiled static assets.

fix

For production deployments, consider using Felt's `--export` option to pre-compile and serve static assets, or implement aggressive caching strategies on your server to mitigate compilation overhead.

affects: >=0.3.0

Errors

Common errors & fixes

Error: Cannot find module 'felt-recipe-minimal'

The `felt-recipe-minimal` package (or another specified recipe) was not installed, or its path is incorrect.

fix

Install the required recipe: `npm install felt-recipe-minimal` or `npm install -g felt felt-recipe-minimal` if using the CLI globally.

Error: listen EADDRINUSE: address already in use :::3000

The default port 3000 (or a specified port) is already being used by another process on your system.

fix

Change the port Felt uses with the `--port` CLI option (e.g., `felt --port 3333`) or by setting the `port` option in your `felt.config.js`.

ReferenceError: require is not defined (at file:///path/to/server.js:...) or SyntaxError: Cannot use import statement outside a module

Attempting to use CommonJS `require()` in an ES module context or vice-versa, indicating a module system mismatch.

fix

Ensure your Node.js environment and file types are correctly configured for CommonJS (`.js` files without `"type": "module"` in package.json, or `.cjs` files) when using Felt, as it is a CommonJS library.

Upgrade

Version history

0.2latest on npm

Audit

Dependencies

expressrequiredRequired for using Felt as an Express.js middleware.

felt-recipe-minimalrequiredA common 'recipe' module providing basic bundling handlers, necessary for minimal functionality both in CLI and middleware modes.

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/cognitom/felt ↗

packagehttps://www.npmjs.com/package/felt ↗