Merge pull request #1023 from wKich/issue-1021

Fix no-array-index-key rule exception

Author: ljharb

lib/rules/no-array-index-key.js

@@ -143,7 +143,8 @@ module.exports = {
           }
 
           props.properties.forEach(function (prop) {
-            if (prop.key.name !== 'key') {
+            if (!prop.key || prop.key.name !== 'key') {
+              // { ...foo }
               // { foo: bar }
               return;
             }

tests/lib/rules/no-array-index-key.js

@@ -15,6 +15,7 @@ var RuleTester = require('eslint').RuleTester;
 var parserOptions = {
   ecmaVersion: 6,
   ecmaFeatures: {
+    experimentalObjectRestSpread: true,
     jsx: true
   }
 };
@@ -61,6 +62,11 @@ ruleTester.run('no-array-index-key', rule, {
       parserOptions: parserOptions
     },
 
+    {
+      code: 'foo.map((baz, i) => React.cloneElement(someChild, { ...someChild.props }))',
+      parserOptions: parserOptions
+    },
+
     {
       code: [
         'foo.map((item, i) => {',
@@ -69,7 +75,6 @@ ruleTester.run('no-array-index-key', rule, {
         '  })',
         '})'
       ].join('\n'),
-      errors: [{message: 'Do not use Array index in keys'}],
       parserOptions: parserOptions
     },
 
@@ -131,6 +136,12 @@ ruleTester.run('no-array-index-key', rule, {
       parserOptions: parserOptions
     },
 
+    {
+      code: 'foo.map((baz, i) => React.cloneElement(someChild, { ...someChild.props, key: i }))',
+      errors: [{message: 'Do not use Array index in keys'}],
+      parserOptions: parserOptions
+    },
+
     {
       code: [
         'foo.map((item, i) => {',