Inline matchResource#

Inline matchResource allows you to dynamically change the matching rules when loading resources. You can set the matchResource for a module specifier by prefixing <match-resource>!=! to the module specifier.

When a matchResource is set, it will be used to match with the module.rules instead of the original resource. This can be useful if further loaders should be applied to the resource, or if the module type needs to be changed.

Example#

/* STYLE: body { background: red; } */
console.log('yep');

A loader could transform the file into the following file and use the matchResource to apply the user-specified CSS processing rules:

import './file.js.css!=!extract-style-loader/getStyles!./file.js';
console.log('yep');

This will add a dependency to extract-style-loader/getStyles!./file.js and treat the result as file.js.css. Because module.rules has a rule matching /\.css$/ and it will apply to this dependency.

The loader could look like this:

const getStylesLoader = require.resolve('./getStyles');

module.exports = function (source) {
  if (STYLES_REGEXP.test(source)) {
    source = source.replace(STYLES_REGEXP, '');
    return `import ${JSON.stringify(
      this.utils.contextify(
        this.context || this.rootContext,
        `${this.resource}.css!=!${getStylesLoader}!${this.remainingRequest}`,
      ),
    )};${source}`;
  }
  return source;
};

module.exports = function (source) {
  const match = source.match(STYLES_REGEXP);
  return match[0];
};