--- /dev/null
+"use strict";
+
+const atRuleParamIndex = require("../utils/atRuleParamIndex");
+const report = require("../utils/report");
+const styleSearch = require("style-search");
+
+module.exports = function(opts) {
+ opts.root.walkAtRules(/^media$/i, atRule => {
+ const params = atRule.params;
+ styleSearch({ source: params, target: "," }, match => {
+ checkComma(params, match.startIndex, atRule);
+ });
+ });
+
+ function checkComma(source, index, node) {
+ opts.locationChecker({
+ source,
+ index,
+ err: m =>
+ report({
+ message: m,
+ node,
+ index: index + atRuleParamIndex(node),
+ result: opts.result,
+ ruleName: opts.checkedRuleName
+ })
+ });
+ }
+};