rev-web-assets

Revision web asset filenames with cache busting content hash fingerprints

rev-web-assets updates the asset filenames of a website to contain a eight-digit hex hash.  The command's console output includes a timestamp and formatting helpful in build systems.

A) Setup

Install package for node:

$ npm install --save-dev rev-web-assets

B) Usage

1. Synopsis

rev-web-assets [SOURCE] [TARGET]

Parameters:

• The first parameter is the source folder.
• The second parameter is the target folder.

2. npm package.json scripts

Run rev-web-assets from the "scripts" section of your package.json file.

Example package.json scripts:

   "scripts": {
      "revision": "rev-web-assets build/dev/web-app build/prod/web-app"
   },

3. Command-line npx

Example terminal commands:

$ npm install --save-dev rev-web-assets
$ npx rev-web-assets build/dev/web-app build/prod/web-app

You can also install rev-web-assets globally (--global) and then run it anywhere directly from the terminal.

4. CLI flags

Command-line flags:

Flag	Description	Value
--cd	Change working directory before starting.	string
--force	Revision (hash) all asset files even if not referenced.	N/A
--hide404s	Suppress warning messages about missing asset files.	N/A
--manifest	Output the list of files to: manifest.json	N/A
--meta-content-base	Make meta URLs, like "og:image", absolute.	string
--note	Place to add a comment only for humans.	string
--quiet	Suppress informational messages.	N/A
--skip	Do not revision (hash) asset files with paths containing given string.	string
--summary	Only print out the single line summary message.	N/A

5. Examples

• rev-web-assets web/source web/target
  Revisions the files in the web/source folder and saves the new files to the web/target folder.

• rev-web-assets --cd=web source target
  Identical to the previous example.

• rev-web-assets source target --quiet
  Displays no output.

• rev-web-assets source target --summary
  Displays the summary informaion but not informaion about individual filenames.

• rev-web-assets source 'target/Web Files' --summary
  Save the target files to a folder that has a space in its name.

• rev-web-assets source target --meta-content-base=https://example.net
  Prepends the base to <meta> URLs.

Note

Single quotes in commands are normalized so they work cross-platform and avoid the errors often encountered on Microsoft Windows.

URLs in <meta> tag content attributes generally need to be absolute URLs.  Setting the --meta-content-base flag to https://example.net will transform the line of HTML from:

<meta property=og:image content="logo.png">

into something like:

<meta property=og:image content="https://example.net/logo.ad41b20.png">

6. Manifest

The --manifest flag produces a JSON file containing an array objects with details about each file:

export type ManifestDetail = {
   origin:          string,          //source path of asset file
   filename:        string,          //source filename of asset file
   canonical:       string,          //normalized path used to lookup asset in manifest
   canonicalFolder: string,          //directory of the normalized path of the asset file
   isHtml:          boolean,         //asset file is HTML
   isCss:           boolean,         //asset file is CSS
   bytes:           number | null,   //asset file size
   hash:            string | null,   //eight-digit cache busting hex humber that changes if the asset changes
   hashedFilename:  string | null,   //filename of the asset with hash inserted before the file extension
   destFolder:      string,          //directory of the target asset
   destPath:        string | null,   //folder and filename of the target asset
   usedIn:          string[] | null, //files that references the asset
   references:      number | null,   //number of times the asset is referenced
   skipped:         boolean,         //asset file is configured to not be hashed
   };

Example:

   {
      "origin": "src/website/graphics/logo.png",
      "filename": "logo.png",
      "canonicalFolder": "graphics",
      "canonical": "graphics/logo.png",
      "bytes": 7203,
      "isHtml": false,
      "isCss": false,
      "hash": "ad42b203",
      "hashedFilename": "logo.ad42b203.png",
      "destFolder": "target/website/graphics",
      "destPath": "target/website/graphics/logo.ad42b203.png",
      "usedIn": [
         "index.html",
         "products/index.html",
         "style.css",
      ],
      "references": 7
   },

C) Application Code

Even though rev-web-assets is primarily intended for build scripts, the package can be used programmatically in ESM and TypeScript projects.

Example:

import { revWebAssets } from 'rev-web-assets';

const options = { saveManifest: true };
const results = revWebAssets.revision('source', 'target', options);
console.info('Number of web files processed:', results.count);

See the TypeScript Declarations at the top of rev-web-assets.ts for documentation.

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MIT License

🛡️ npm Security Aggregator

See the runScriptsConfig section of package.json for a clean way to organize build tasks:

• 🎋 add-dist-header —  Prepend a one-line banner comment (with license notice) to distribution files
• 📄 copy-file-util —  Copy or rename a file with optional package version number
• 📂 copy-folder-util —  Recursively copy files from one folder to another folder
• 🪺 recursive-exec —  Run a command on each file in a folder and its subfolders
• 🔍 replacer-util —  Find and replace strings or template outputs in text files
• 🔢 rev-web-assets —  Revision web asset filenames with cache busting content hash fingerprints
• 🚆 run-scripts-util —  Organize npm package.json scripts into groups of easy-to-manage commands
• 🚦 w3c-html-validator —  Check the markup validity of HTML files using the W3C validator