Fix: no-unsupported-features crash if only ignores option

lib/rules/no-unsupported-features.js

@@ -154,20 +154,25 @@ function isIgnored(key, ignores) {
  * Parses the options.
  *
  * @param {object} options - An option object to parse.
+ * @param {number} defaultVersion - The default version to use if the version option was omitted.
  * @returns {object} Parsed value.
  */
-function parseOptions(options) {
+function parseOptions(options, defaultVersion) {
     var version = 0
     var ignores = null
 
     if (typeof options === "number") {
-        version = options
+        version = options || defaultVersion
         ignores = []
     }
-    else {
-        version = options.version
+    else if (typeof options === "object") {
+        version = options.version || defaultVersion
         ignores = options.ignores || []
     }
+    else {
+        version = defaultVersion
+        ignores = []
+    }
 
     return Object.freeze({
         version: version < 1 ? version.toFixed(2) : version.toFixed(0),
@@ -259,7 +264,8 @@ function hasUnicodeCodePointEscape(raw) {
 module.exports = function(context) {
     var sourceCode = context.getSourceCode()
     var supportInfo = parseOptions(
-        context.options[0] || getDefaultVersion(context.getFilename())
+        context.options[0],
+        getDefaultVersion(context.getFilename())
     )
     var hasSpecialLexicalEnvironment = checkSpecialLexicalEnvironment(context)
 

tests/lib/rules/no-unsupported-features.js

@@ -1028,6 +1028,12 @@ ruleTester.run("no-unsupported-features", rule, [
             code: "'\\\\u{0123}'",
             env: {es6: true},
         },
+        {
+            filename: fixture("gte-4.0.0/a.js"),
+            code: "var a = async () => 1",
+            parserOptions: {ecmaVersion: 2017},
+            options: [{ignores: ["asyncAwait"]}],
+        },
     ],
     invalid: [
         {