Fix crash in no-nonstandard-*-properties rules (#234)

Author: ota-meshi

lib/util/get-property-key-value.js

@@ -55,9 +55,10 @@ function getPropertyKeyValue(node, initialScope) {
  */
 function getStaticKeyValue(node, initialScope) {
     const value = getStaticValue(node, initialScope)
-    return value && typeof value.value === "symbol"
-        ? value.value
-        : String(value.value)
+    return (
+        value &&
+        (typeof value.value === "symbol" ? value.value : String(value.value))
+    )
 }
 
 module.exports = { getPropertyKeyValue }

tests/lib/rules/no-nonstandard-array-prototype-properties.js

@@ -22,6 +22,8 @@ new RuleTester().run(ruleId, rule, {
         { code: "['A'].unknown()", options: [{ allow: ["unknown"] }] },
         // Test for https://github.com/eslint-community/eslint-plugin-es-x/issues/223
         "for (const { x } of foo) {}",
+        // Test for https://github.com/eslint-community/eslint-plugin-es-x/issues/233
+        "['A'][unknown];",
     ],
     invalid: [
         {