get rid of no-undefined eslint rule

Author: alexcjohnson

Diff for: dash-renderer/.eslintrc.json

@@ -110,7 +110,6 @@
       "no-sequences": ["error"],
       "no-shadow": ["off"],
       "no-throw-literal": ["error"],
-      "no-undefined": ["error"],
       "no-unused-expressions": ["error"],
       "no-use-before-define": ["error", "nofunc"],
       "no-useless-call": ["error"],
@@ -147,4 +146,4 @@
       "no-underscore-dangle": ["off"],
       "no-useless-escape": ["off"]
     }
-  }
+  }

Diff for: dash-renderer/src/persistence.js

@@ -100,8 +100,8 @@ function keyPrefixMatch(prefix, separator) {
 }
 
 const UNDEFINED = 'U';
-const _parse = val => (val === UNDEFINED ? void 0 : JSON.parse(val || null));
-const _stringify = val => (val === void 0 ? UNDEFINED : JSON.stringify(val));
+const _parse = val => (val === UNDEFINED ? undefined : JSON.parse(val || null));
+const _stringify = val => (val === undefined ? UNDEFINED : JSON.stringify(val));
 
 class WebStore {
     constructor(backEnd) {

Diff for: dash-renderer/tests/persistence.test.js

@@ -1,5 +1,4 @@
 /* eslint-disable no-magic-numbers */
-/* eslint-disable no-undefined */
 /* eslint-disable no-console */
 import {recordUiEdit, stores, storePrefix} from '../src/persistence';