index.js

// Abbreviated example
var stylelint = require('stylelint');

var ruleName = 'stylelint/regex';
var messages = stylelint.utils.ruleMessages(ruleName, {
  expected: 'Expected ...'
});

module.exports = stylelint.createPlugin(ruleName, function(
  primaryOption,
  secondaryOptionObject
) {
  return function(postcssRoot, postcssResult) {
    var validOptions = stylelint.utils.validateOptions(
      postcssResult,
      ruleName,
      primaryOption
    );

    if (!validOptions) {
      return;
    }

    const fileName = postcssRoot.source.input.file;
    const css = postcssRoot.source.input.css;
    let m;

    if (secondaryOptionObject.ignore.some(f => fileName.indexOf(f) > -1)) {
      return;
    }

    primaryOption.forEach(o => {
      for (regex in o) {
        const message = o[regex];
        m = new RegExp(regex, 'gm').exec(css);
        if (m) {
          stylelint.utils.report({
            message: message + ' has been violated in ' + fileName,
            ruleName: ruleName,
            result: postcssResult,
            node: postcssRoot
          });
        }
      }
    });
  };
});

module.exports.ruleName = ruleName;
module.exports.messages = messages;