index.js

var _ = require('lodash');
var stylelint = require('stylelint');

var ruleName = 'plugin/stylelint-force-app-name-prefix';

var optionsSchema = {
  appName: _.isString
};

const messages = stylelint.utils.ruleMessages(ruleName, {
  invalid: (selector, appName) => "Selector \""+ selector +"\" is out of control, please wrap within ." + appName,
  invalidKeyFrames: (keyframesName, appName) => "Keyframes name \""+ keyframesName +"\" is out of control, please prefix with " + appName + "-",
  invalidFontFace: (fontFamily, appName) => "Custom font-family \""+ fontFamily +"\" is out of control, please prefix with " + appName + "-"
})

function findTopParentSelector(node) {
  if (node.parent.type === 'root' || node.parent.type === 'atrule') {
    return node.selector
  } else {
    return findTopParentSelector(node.parent)
  }
}

function isInsideAtRule(node) {
  if (node.parent.type === 'atrule') {
    return true;
  } else if (node.parent.type === 'root'){
    return false;
  } else {
    return findTopParentSelector(node.parent)
  }
}

module.exports = stylelint.createPlugin(ruleName, function(options) {
  return function(root, result) {
    if (!options) return;
    var validOptions = stylelint.utils.validateOptions(result, ruleName, {
      actual: options,
      possible: optionsSchema,
    });
    if (!validOptions) return;

    const whiteList = [
      '.' + options.appName,
      /^:.*/
    ]

    root.walkAtRules('keyframes', rule => {
      const keyframesName = rule.params

      if (keyframesName.indexOf(options.appName + '-') === -1) {
        stylelint.utils.report({
          ruleName: ruleName,
          result: result,
          node: rule,
          message: messages.invalidKeyFrames(keyframesName, options.appName)
        })
      }
    })

    root.walkAtRules('font-face', rule => {
      rule.walkDecls('font-family', (decl) => {
        if (decl.value.indexOf(options.appName + '-') === -1) {
          stylelint.utils.report({
            ruleName: ruleName,
            result: result,
            node: rule,
            message: messages.invalidFontFace(decl.value, options.appName)
          })
        }
      })
    })

    root.walkRules(rule => {
      if (isInsideAtRule(rule)) return;
      const topParentSelector = findTopParentSelector(rule);
      if (whiteList.find(function (whiteRule) {
        if (whiteRule instanceof RegExp) {
          return whiteRule.test(topParentSelector)
        } else {
          return whiteRule === topParentSelector;
        }
      })) {
        // in white list, skipped
        return;
      }

      if (topParentSelector.indexOf('.' + options.appName + ' ') === 0) {
        // good
      } else {
        stylelint.utils.report({
          ruleName: ruleName,
          result: result,
          node: rule,
          message: messages.invalid(rule.selector, options.appName)
        })
      }
    })
  };
});

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