--- /dev/null
+/* @flow */
+"use strict";
+
+const _ = require("lodash");
+const keywordSets = require("../reference/keywordSets");
+
+/**
+ * Check value is a custom ident
+ */
+
+module.exports = function(value /*: string*/) /*: boolean*/ {
+ const valueLowerCase = value.toLowerCase();
+
+ if (
+ keywordSets.counterResetKeywords.has(valueLowerCase) ||
+ _.isFinite(parseInt(valueLowerCase))
+ ) {
+ return false;
+ }
+
+ return true;
+};