express-dart-sass

1.0.4 verified Sat Apr 25 auth: no javascript maintenance

Express middleware for dart-sass (the primary Sass implementation, now deprecated in favor of the new JS API). Version 1.0.4 is the latest stable release (last updated in 2021). It recompiles .scss/.sass files automatically for Express-based HTTP servers. Key differentiators: uses dart-sass (which is faster and more feature-complete than node-sass), supports legacy options like outputStyle, prefix, and error handling. The package is in maintenance mode due to the deprecation of the legacy JS API (LibSass/Node Sass) and the move to the new embedded dart-sass API.

Common errors

error Error: Cannot find module 'sass' ↓

cause The package depends on dart-sass (the `sass` npm package) which is not installed.

fix

npm install sass --save

error TypeError: sassMiddleware is not a function ↓

cause CommonJS require returns an object with a default property when using ESM-style import in a CJS environment? Actually, the package exports a function directly, but if you use `import sassMiddleware from 'express-dart-sass'` in a TypeScript project with esModuleInterop: false, it may cause issues.

fix

Use const sassMiddleware = require('express-dart-sass') or enable esModuleInterop in tsconfig.

Warnings

deprecated The dart-sass legacy JS API (used by this middleware) is deprecated in favor of the new compile() API. ↓

fix Consider migrating to sass (dart-sass) direct integration or use the new compile API in your own middleware.

gotcha Middleware must be placed before express.static to serve compiled CSS. ↓

fix Ensure app.use(sassMiddleware(...)) precedes app.use(express.static(...)).

gotcha The 'dest' option is required; if omitted, compiled files may overwrite source .scss files (since default is src). ↓

fix Always specify dest or use response: true if you don't need file output.

Install

npm install express-dart-sass

yarn add express-dart-sass

pnpm add express-dart-sass

Imports

default

wrong

import sassMiddleware from 'express-dart-sass';

correct

const sassMiddleware = require('express-dart-sass');

This package is CommonJS only; it does not provide ESM exports. Use require().

default (ESM style)
wrong
```
import { sass } from 'express-dart-sass';
```
correct
```
import sassMiddleware from 'express-dart-sass';
// Works only if your project is configured for ESM interop.
```
The package's module field points to an ESM wrapper? Actually it's CJS; some bundlers allow default import. Named import does not exist.
Options interface
wrong
```
import { Options } from 'express-dart-sass';
```
correct
```
// No type exports; define your own interface based on docs
```
The package does not ship TypeScript declarations. Use @types/express-dart-sass? There are none.

Quickstart

Sets up express-dart-sass middleware to compile SCSS files from src to dest with compressed output, then serves static files.

const express = require('express');
const sassMiddleware = require('express-dart-sass');
const path = require('path');
const app = express();

app.use(sassMiddleware({
    src: __dirname,
    dest: path.join(__dirname, 'public'),
    debug: true,
    outputStyle: 'compressed',
    prefix: '/prefix'
}));

app.use(express.static(path.join(__dirname, 'public')));

app.listen(3000, () => console.log('Server running on port 3000'));