CSS URL Rewriter

Features

• Designed to be used as dependency for other libraries (sass, less, stylus etc)
• Rewrite CSS URLs to project root path with default resolver
• Rewrite CSS URLs with custom URL resolver
• Track all processed URLs
• Could be used in combination with css-asset-copier library

TODO

• By default this rewriter modify code only inside lines, so it source code line number is preserved but column could be different, but precise column level mapping for css has no benefits while debugging. But it could be implemented using source-map npm package.
• Implement more precise parser using css npm package.

Installation

npm install css-url-rewriter-ex

Usage

Default Resolver

• root: specify path to project root folder which will be used to resolve all relative urls.
• publicPath: set to target public path to prefix relative paths with it. Required for <link href="blob:..."/> or <link href="data:..."/> style injections for some browsers, for example, for Chrome 54.x (otherwise Chrome will not be able to resolve relative urls).

var CssUrlRewriter = require('css-url-rewriter-ex');
var rewriter = new CssUrlRewriter({ root: path.resolve('.') });
var fixedContent = rewriter.rewrite(filename, originalContent);

Custom Resolver

• Pass resolver option as function resolver(url, filename, option) { ... }
• absolute and data urls are not resolved by default
• return false to skip rewrite
• return undefined or null to use default resolver
• return string with resolved url to use it

var CssUrlRewriter = require('css-url-rewriter-ex');

var rewriter = new CssUrlRewriter({
  root: SystemJS.baseURL,
  resolver: function (url, filename, options) {
    // resolve jspm: paths here and use default for all others
    if (url.match(/^jspm:/)) {
      return SystemJS.normalizeSync(url.substr(5));
    }
  }
});

var fixedContent = rewriter.rewrite(filename, originalContent);