prepa

A utility for preparing static assets.

Get in on npm: npm install -g prepa or yarn global add prepa

Features

• prepa min - minify your static assets (CSS, JS, SVG)
• prepa zip - precompress your static assets (Gzip, Brotli)
• prepa hash - fingerprint your static assets (for cache busting) with automatic reference fixing

Limitations

• Image optimization is not provided (except for SVG) since it is difficult to automate the following:

  • resizing images based on its actual size on the page
  • the use of multiple image sizes and formats (separate high-DPI versions, WebP with fallback)
  • greater compression (often lossy, which requires subjective judgment)

• Fixing references (after fingerprinting) is limited to the following:

  • href, src, and srcset attributes in HTML
  • url functions in CSS (inline styles are not included)

NOTE: When fixing references, the specified directory is assumed to be the root. References are detected via regular expressions, and no actual parsing is done. This should be sufficient for most cases, but if you wish to handle the fixing yourself, use prepa rename to skip automatic fixing and generate a prepa-renames.json file instead.

Implementation Details

• Minification uses the following libraries: csso for CSS, terser for JS, svgo for SVG

• Compression uses the built-in zlib module of Node.js and is always done at the max level (Brotli support requires Node.js v11.7.0 or later)

• Only CSS, HTML, JS, JSON, SVG, TXT, and XML files are included for compression (other file formats are expected to already be in a compressed format)

• Asset fingerprinting uses BLAKE2b-512 as its hash function, and truncates it to 16 base64 characters (96 bits)

• HTML, JSON, TXT, and XML files are all excluded from fingerprinting