Use Object spread instead of Object.assign where it makes sense (#13903) (#14397)

* Prefer Object spread

* Add eslint rules for Object spread

* no slice

package.json

@@ -209,7 +209,7 @@
     "yauzl": "2.7.0"
   },
   "devDependencies": {
-    "@elastic/eslint-config-kibana": "0.11.0",
+    "@elastic/eslint-config-kibana": "0.12.0",
     "@elastic/eslint-import-resolver-kibana": "0.8.1",
     "@elastic/eslint-plugin-kibana-custom": "1.0.3",
     "angular-mocks": "1.4.7",
@@ -228,6 +228,7 @@
     "eslint-plugin-import": "2.3.0",
     "eslint-plugin-jest": "21.0.0",
     "eslint-plugin-mocha": "4.9.0",
+    "eslint-plugin-prefer-object-spread": "1.2.1",
     "eslint-plugin-react": "7.1.0",
     "event-stream": "3.3.2",
     "expect.js": "0.3.1",

packages/eslint-config-kibana/.eslintrc.js

@@ -6,6 +6,7 @@ module.exports = {
     'babel',
     'react',
     'import',
+    'prefer-object-spread',
   ],
 
   env: {
@@ -132,5 +133,7 @@ module.exports = {
     'import/no-named-as-default': 'error',
     'import/no-named-as-default-member': 'error',
     'import/no-duplicates': 'error',
+
+    'prefer-object-spread/prefer-object-spread': 'error',
   }
 }

packages/eslint-config-kibana/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@elastic/eslint-config-kibana",
-  "version": "0.11.0",
+  "version": "0.12.0",
   "description": "The eslint config used by the kibana team",
   "main": ".eslintrc.js",
   "scripts": {
@@ -24,6 +24,7 @@
     "eslint-plugin-import": "^2.6.0",
     "eslint-plugin-jest": "^21.0.0",
     "eslint-plugin-mocha": "^4.9.0",
+    "eslint-plugin-prefer-object-spread": "^1.2.1",
     "eslint-plugin-react": "^7.1.0"
   }
 }

src/core_plugins/console/server/proxy_config.js

@@ -7,12 +7,16 @@ import { WildcardMatcher } from './wildcard_matcher';
 
 export class ProxyConfig {
   constructor(config) {
-    config = Object.assign({}, config);
+    config = {
+      ...config
+    };
 
     // -----
     // read "match" info
     // -----
-    const rawMatches = Object.assign({}, config.match);
+    const rawMatches = {
+      ...config.match
+    };
     this.id = formatUrl({
       protocol: rawMatches.protocol,
       hostname: rawMatches.host,

src/core_plugins/elasticsearch/lib/__tests__/cluster.js

@@ -92,7 +92,12 @@ describe('plugins/elasticsearch', function () {
 
       it('passes only whitelisted headers', () => {
         const headers = { authorization: 'Basic TEST' };
-        const request = { headers: Object.assign({}, headers, { foo: 'Foo' }) };
+        const request = {
+          headers: {
+            ...headers,
+            foo: 'Foo'
+          }
+        };
 
         cluster.callWithRequest(request, 'nodes.info');
 

src/core_plugins/elasticsearch/lib/cluster.js

@@ -8,7 +8,9 @@ import { parseConfig } from './parse_config';
 
 export class Cluster {
   constructor(config) {
-    this._config = Object.assign({}, config);
+    this._config = {
+      ...config
+    };
     this.errors = elasticsearch.errors;
 
     this._client = this.createClient();
@@ -53,7 +55,10 @@ export class Cluster {
   }
 
   createClient = configOverrides => {
-    const config = Object.assign({}, this._getClientConfig(), configOverrides);
+    const config = {
+      ...this._getClientConfig(),
+      ...configOverrides
+    };
     return new elasticsearch.Client(parseConfig(config));
   }
 

src/core_plugins/elasticsearch/lib/create_admin_cluster.js

@@ -12,7 +12,10 @@ export function createAdminCluster(server) {
 
   const adminCluster = server.plugins.elasticsearch.createCluster(
     'admin',
-    Object.assign({ log: AdminClientLogging }, config.get('elasticsearch'))
+    {
+      log: AdminClientLogging,
+      ...config.get('elasticsearch')
+    }
   );
 
   server.on('close', bindKey(adminCluster, 'close'));

src/core_plugins/elasticsearch/lib/create_data_cluster.js

@@ -20,7 +20,10 @@ export function createDataCluster(server) {
 
   const dataCluster = server.plugins.elasticsearch.createCluster(
     'data',
-    Object.assign({ log: DataClientLogging }, getConfig())
+    {
+      log: DataClientLogging,
+      ...getConfig()
+    }
   );
 
   server.on('close', bindKey(dataCluster, 'close'));

src/core_plugins/elasticsearch/lib/parse_config.js

@@ -7,12 +7,13 @@ import Bluebird from 'bluebird';
 const readFile = (file) => readFileSync(file, 'utf8');
 
 export function parseConfig(serverConfig = {}) {
-  const config = Object.assign({
-    keepAlive: true
-  }, pick(serverConfig, [
-    'plugins', 'apiVersion', 'keepAlive', 'pingTimeout',
-    'requestTimeout', 'log', 'logQueries'
-  ]));
+  const config = {
+    keepAlive: true,
+    ...pick(serverConfig, [
+      'plugins', 'apiVersion', 'keepAlive', 'pingTimeout',
+      'requestTimeout', 'log', 'logQueries'
+    ])
+  };
 
   const uri = url.parse(serverConfig.url);
   config.host = {

src/core_plugins/kibana/public/context/api/anchor.js

@@ -30,13 +30,10 @@ function fetchAnchorProvider(courier, Private) {
       throw new Error('Failed to load anchor document.');
     }
 
-    return Object.assign(
-      {},
-      _.get(response, ['hits', 'hits', 0]),
-      {
-        $$_isAnchor: true,
-      },
-    );
+    return {
+      ..._.get(response, ['hits', 'hits', 0]),
+      $$_isAnchor: true,
+    };
   };
 }
 

src/core_plugins/kibana/public/context/app.js

@@ -59,11 +59,10 @@ function ContextAppController($scope, config, Private, timefilter) {
     this.discoverUrl,
   );
 
-  this.actions = _.mapValues(Object.assign(
-    {},
-    queryParameterActions,
-    queryActions,
-  ), (action) => (...args) => action(this.state)(...args));
+  this.actions = _.mapValues({
+    ...queryParameterActions,
+    ...queryActions,
+  }, (action) => (...args) => action(this.state)(...args));
 
   this.constants = {
     FAILURE_REASONS,

src/core_plugins/kibana/public/dashboard/dashboard_state.js

@@ -122,7 +122,7 @@ export class DashboardState {
     // in place in order for it to affect the visualizations.
     this.stateDefaults.query = this.lastSavedDashboardFilters.query;
     // Need to make a copy to ensure they are not overwritten.
-    this.stateDefaults.filters = Object.assign(new Array(), this.getLastSavedFilterBars());
+    this.stateDefaults.filters = [...this.getLastSavedFilterBars()];
 
     this.isDirty = false;
     this.appState.setDefaults(this.stateDefaults);

src/core_plugins/kibana/public/discover/components/field_chooser/field_chooser.js

@@ -214,17 +214,15 @@ app.directive('discFieldChooser', function ($location, globalState, config, $rou
 
       $scope.computeDetails = function (field, recompute) {
         if (_.isUndefined(field.details) || recompute) {
-          field.details = Object.assign(
-            {
-              visualizeUrl: field.visualizable ? getVisualizeUrl(field) : null,
-            },
-            fieldCalculator.getFieldValueCounts({
+          field.details = {
+            visualizeUrl: field.visualizable ? getVisualizeUrl(field) : null,
+            ...fieldCalculator.getFieldValueCounts({
               hits: $scope.hits,
               field: field,
               count: 5,
               grouped: false
             }),
-          );
+          };
           _.each(field.details.buckets, function (bucket) {
             bucket.display = field.format.convert(bucket.value);
           });

src/core_plugins/metrics/public/components/aggs/agg.js

@@ -10,7 +10,10 @@ function Agg(props) {
   if (!Component) {
     Component = StdAgg;
   }
-  const style = Object.assign({ cursor: 'default' }, props.style);
+  const style = {
+    cursor: 'default',
+    ...props.style
+  };
   return (
     <div
       aria-hidden="true"

src/ui/public/courier/__tests__/saved_object.js

@@ -26,14 +26,13 @@ describe('Saved Object', function () {
    * @returns {{attributes: {}, type: string, id: *, _version: integer}}
    */
   function getMockedDocResponse(indexPatternId, additionalOptions = {}) {
-    return Object.assign(
-      {
-        type: 'dashboard',
-        id: indexPatternId,
-        _version: 2,
-        attributes: {}
-      },
-      additionalOptions);
+    return {
+      type: 'dashboard',
+      id: indexPatternId,
+      _version: 2,
+      attributes: {},
+      ...additionalOptions
+    };
   }
 
   /**
@@ -481,10 +480,11 @@ describe('Saved Object', function () {
     describe('defaults', function () {
 
       function getTestDefaultConfig(extraOptions) {
-        return Object.assign({
+        return {
           defaults: { testDefault: 'hi' },
-          type: 'dashboard'
-        }, extraOptions);
+          type: 'dashboard',
+          ...extraOptions
+        };
       }
 
       function expectDefaultApplied(config) {

src/ui/public/courier/data_source/build_query/from_kuery.js

@@ -5,12 +5,13 @@ export function buildQueryFromKuery(indexPattern, queries) {
   const queryASTs = _.map(queries, query => fromKueryExpression(query.query));
   const compoundQueryAST = nodeTypes.function.buildNode('and', queryASTs);
   const kueryQuery = toElasticsearchQuery(compoundQueryAST, indexPattern);
-  return Object.assign({
+  return {
     must: [],
     filter: [],
     should: [],
     must_not: [],
-  }, kueryQuery.bool);
+    ...kueryQuery.bool
+  };
 }
 
 

src/ui/public/kbn_top_nav/kbn_top_nav_controller.js

@@ -68,12 +68,13 @@ export function KbnTopNavControllerProvider($compile) {
     }
     // apply the defaults to individual options
     _applyOptDefault(opt = {}) {
-      const defaultedOpt = Object.assign({
+      const defaultedOpt = {
         label: capitalize(opt.key),
         hasFunction: !!opt.run,
         description: opt.run ? opt.key : `Toggle ${opt.key} view`,
-        run: (item) => this.toggle(item.key)
-      }, opt);
+        run: (item) => this.toggle(item.key),
+        ...opt
+      };
 
       defaultedOpt.hideButton = isFunction(opt.hideButton) ? opt.hideButton : () => !!opt.hideButton;
       defaultedOpt.disableButton = isFunction(opt.disableButton) ? opt.disableButton : () => !!opt.disableButton;

src/ui/public/kuery/ast/ast.js

@@ -10,7 +10,10 @@ export function fromKueryExpression(expression, parseOptions = {}) {
     throw new Error('expression must be a string, got undefined instead');
   }
 
-  parseOptions = Object.assign({}, parseOptions, { helpers: { nodeTypes } });
+  parseOptions = {
+    ...parseOptions,
+    helpers: { nodeTypes }
+  };
 
   return kueryParser.parse(expression, parseOptions);
 }

src/ui/public/query_bar/directive/query_bar.js

@@ -36,7 +36,9 @@ module.directive('queryBar', function () {
       };
 
       $scope.$watch('queryBar.query', (newQuery) => {
-        this.localQuery = Object.assign({}, newQuery);
+        this.localQuery = {
+          ...newQuery
+        };
       }, true);
     })
   };

src/ui/public/state_management/state_hashing/hash_url.js

@@ -31,7 +31,10 @@ const hashStatesInQuery = (states, query) => {
   }, {});
 
 
-  return Object.assign({}, query, hashedQuery);
+  return {
+    ...query,
+    ...hashedQuery
+  };
 };
 
 export const hashUrl = (states, redirectUrl) => {

tasks/release_packages.js

@@ -37,10 +37,11 @@ export default (grunt) => {
       rpm.filePath,
       '-r', 'external-1'
     ], {
-      env: Object.assign({}, {
+      env: {
         'AWS_ACCESS_KEY': rpm.awsKey,
-        'AWS_SECRET_KEY': rpm.awsSecret
-      }, process.env)
+        'AWS_SECRET_KEY': rpm.awsSecret,
+        ...process.env
+      }
     });
   }
 

test/functional/page_objects/common_page.js

@@ -29,10 +29,11 @@ export function CommonPageProvider({ getService, getPageObjects }) {
      * @param {string} subUrl The route after the hash (#)
      */
     navigateToUrl(appName, subUrl) {
-      const appConfig = Object.assign({}, config.get(['apps', appName]), {
+      const appConfig = {
+        ...config.get(['apps', appName]),
         // Overwrite the default hash with the URL we really want.
         hash: `${appName}/${subUrl}`,
-      });
+      };
 
       const appUrl = getUrl.noAuth(config.get('servers.kibana'), appConfig);
       return remote.get(appUrl);

ui_framework/doc_site/src/services/example/create_example.js

@@ -10,7 +10,9 @@ export default function creatExample(examples) {
     }
   }
 
-  Example.propTypes = Object.assign({}, GuideExample.propTypes);
+  Example.propTypes = {
+    ...GuideExample.propTypes
+  };
 
   return Example;
 }

ui_framework/doc_site/src/store/reducers/code_viewer_reducer.js

@@ -16,26 +16,29 @@ export default function codeViewerReducer(state = defaultState, action) {
 
       if (state.code === source) {
         // If we are opening the existing code, then close the viewer.
-        return Object.assign({}, state, {
+        return {
+          ...state,
           isOpen: false,
           source: undefined,
           title: undefined,
-        });
+        };
       }
 
-      return Object.assign({}, state, {
+      return {
+        ...state,
         isOpen: true,
         source,
         title,
-      });
+      };
     }
 
     case LOCATION_CHANGE: // Close Code Viewer when we navigate somewhere.
     case ActionTypes.CLOSE_CODE_VIEWER: {
-      return Object.assign({}, state, {
+      return {
+        ...state,
         isOpen: false,
         source: undefined,
-      });
+      };
     }
 
     default:

ui_framework/doc_site/src/store/reducers/sandbox_reducer.js

@@ -7,15 +7,17 @@ const defaultState = {
 export default function sandboxReducer(state = defaultState, action) {
   switch (action.type) {
     case ActionTypes.OPEN_SANDBOX: {
-      return Object.assign({}, state, {
+      return {
+        ...state,
         isSandbox: true,
-      });
+      };
     }
 
     case ActionTypes.CLOSE_SANDBOX: {
-      return Object.assign({}, state, {
+      return {
+        ...state,
         isSandbox: false,
-      });
+      };
     }
 
     default:

ui_framework/doc_site/src/store/reducers/sections_reducer.js

@@ -13,9 +13,10 @@ export default function sectionsReducer(state = defaultState, action) {
         name: action.name,
       });
 
-      return Object.assign({}, state, {
-        sections,
-      });
+      return {
+        ...state,
+        sections: sections,
+      };
     }
 
     case ActionTypes.UNREGISTER_SECTION: {
@@ -23,9 +24,10 @@ export default function sectionsReducer(state = defaultState, action) {
       const index = sections.findIndex(section => section.id === action.id);
       sections.splice(index, 1);
 
-      return Object.assign({}, state, {
-        sections,
-      });
+      return {
+        ...state,
+        sections: sections,
+      };
     }
 
     default:

ui_framework/src/components/accessibility/screen_reader.js

@@ -6,9 +6,10 @@ import classNames from 'classnames';
 export const KuiScreenReaderOnly = ({ children }) => {
   const classes = classNames('kuiScreenReaderOnly', children.props.className);
 
-  const props = Object.assign({}, children.props, {
-    className: classes
-  });
+  const props = {
+    ...children.props,
+    className: classes,
+  };
 
   return cloneElement(children, props);
 };

ui_framework/src/components/outside_click_detector/outside_click_detector.js

@@ -36,11 +36,12 @@ export class KuiOutsideClickDetector extends Component {
   }
 
   render() {
-    const props = Object.assign({}, this.props.children.props, {
+    const props = {
+      ...this.props.children.props,
       ref: node => {
         this.wrapperRef = node;
       },
-    });
+    };
 
     const child = Children.only(this.props.children);
     return cloneElement(child, props);