diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4efa82d5ee7..110188111a8c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -153,6 +153,7 @@
 - `[*]` Standardize file names ([#7316](https://github.com/facebook/jest/pull/7316), [#7266](https://github.com/facebook/jest/pull/7266), [#7238](https://github.com/facebook/jest/pull/7238), [#7314](https://github.com/facebook/jest/pull/7314), [#7467](https://github.com/facebook/jest/pull/7467), [#7464](https://github.com/facebook/jest/pull/7464)), [#7471](https://github.com/facebook/jest/pull/7471))
 - `[docs]` Add `testPathIgnorePatterns` in CLI documentation ([#7440](https://github.com/facebook/jest/pull/7440))
 - `[docs]` Removed misleading text about `describe()` grouping together tests into a test suite ([#7434](https://github.com/facebook/jest/pull/7434))
+- `[*]` Replace as many `Object.assign` with object spread as possible
 
 ### Performance
 
diff --git a/TestUtils.js b/TestUtils.js
index 1c2ec68398ec..33c9e93490e2 100644
--- a/TestUtils.js
+++ b/TestUtils.js
@@ -134,7 +134,7 @@ export const makeGlobalConfig = (overrides: Object = {}): GlobalConfig => {
     `);
   }
 
-  return Object.assign({}, DEFAULT_GLOBAL_CONFIG, overrides);
+  return {...DEFAULT_GLOBAL_CONFIG, ...overrides};
 };
 
 export const makeProjectConfig = (overrides: Object = {}): ProjectConfig => {
@@ -148,5 +148,5 @@ export const makeProjectConfig = (overrides: Object = {}): ProjectConfig => {
     `);
   }
 
-  return Object.assign({}, DEFAULT_PROJECT_CONFIG, overrides);
+  return {...DEFAULT_GLOBAL_CONFIG, ...overrides};
 };
diff --git a/e2e/runJest.js b/e2e/runJest.js
index cb67e53545ac..9095e9a54a39 100644
--- a/e2e/runJest.js
+++ b/e2e/runJest.js
@@ -49,7 +49,7 @@ export default function runJest(
     );
   }
 
-  const env = Object.assign({}, process.env, {FORCE_COLOR: 0});
+  const env = {...process.env, FORCE_COLOR: 0};
   if (options.nodePath) env['NODE_PATH'] = options.nodePath;
   const result = spawnSync(JEST_PATH, args || [], {
     cwd: dir,
@@ -119,7 +119,7 @@ export const until = async function(
     );
   }
 
-  const env = Object.assign({}, process.env, {FORCE_COLOR: 0});
+  const env = {...process.env, FORCE_COLOR: 0};
   if (options.nodePath) env['NODE_PATH'] = options.nodePath;
 
   const jestPromise = execa(JEST_PATH, args || [], {
diff --git a/examples/module-mock/__tests__/partial_mock.js b/examples/module-mock/__tests__/partial_mock.js
index 21077480ad1d..7e2b92434e13 100644
--- a/examples/module-mock/__tests__/partial_mock.js
+++ b/examples/module-mock/__tests__/partial_mock.js
@@ -12,10 +12,12 @@ jest.mock('../fruit', () => {
   const mockedModule = jest.genMockFromModule('../fruit');
 
   //Mock the default export and named export 'apple'.
-  return Object.assign({}, mockedModule, originalModule, {
+  return {
+    ...mockedModule,
+    ...originalModule,
     apple: 'mocked apple',
     default: jest.fn(() => 'mocked fruit'),
-  });
+  };
 });
 
 it('does a partial mock', () => {
diff --git a/packages/expect/src/index.js b/packages/expect/src/index.js
index c570fb8a41a9..ca6cacf16e3b 100644
--- a/packages/expect/src/index.js
+++ b/packages/expect/src/index.js
@@ -234,27 +234,22 @@ const makeThrowingMatcher = (
 ): ThrowingMatcherFn =>
   function throwingMatcher(...args): any {
     let throws = true;
-    const utils = Object.assign({}, matcherUtils, {
-      iterableEquality,
-      subsetEquality,
-    });
+    const utils = {...matcherUtils, iterableEquality, subsetEquality};
 
-    const matcherContext: MatcherState = Object.assign(
+    const matcherContext: MatcherState = {
       // When throws is disabled, the matcher will not throw errors during test
       // execution but instead add them to the global matcher state. If a
       // matcher throws, test execution is normally stopped immediately. The
       // snapshot matcher uses it because we want to log all snapshot
       // failures in a test.
-      {dontThrow: () => (throws = false)},
-      getState(),
-      {
-        equals,
-        error: err,
-        isNot,
-        promise,
-        utils,
-      },
-    );
+      dontThrow: () => (throws = false),
+      ...getState(),
+      equals,
+      error: err,
+      isNot,
+      promise,
+      utils,
+    };
 
     const processResult = (result: SyncExpectationResult) => {
       _validateResult(result);
diff --git a/packages/jest-changed-files/src/hg.js b/packages/jest-changed-files/src/hg.js
index 7e1294fa42cd..9459619fcc6c 100644
--- a/packages/jest-changed-files/src/hg.js
+++ b/packages/jest-changed-files/src/hg.js
@@ -13,9 +13,7 @@ import type {Options, SCMAdapter} from 'types/ChangedFiles';
 import path from 'path';
 import execa from 'execa';
 
-const env = Object.assign({}, process.env, {
-  HGPLAIN: 1,
-});
+const env = {...process.env, HGPLAIN: 1};
 
 const ANCESTORS = [
   // Parent commit to this one.
diff --git a/packages/jest-changed-files/src/index.js b/packages/jest-changed-files/src/index.js
index c1ad572adbbd..f7ecf3d8fb1d 100644
--- a/packages/jest-changed-files/src/index.js
+++ b/packages/jest-changed-files/src/index.js
@@ -27,7 +27,7 @@ export const getChangedFilesForRoots = async (
 ): ChangedFilesPromise => {
   const repos = await findRepos(roots);
 
-  const changedFilesOptions = Object.assign({}, {includePaths: roots}, options);
+  const changedFilesOptions = {includePaths: roots, ...options};
 
   const gitPromises = Array.from(repos.git).map(repo =>
     git.findChangedFiles(repo, changedFilesOptions),
diff --git a/packages/jest-cli/src/FailedTestsCache.js b/packages/jest-cli/src/FailedTestsCache.js
index 46ae69b1aadf..73c0970e1646 100644
--- a/packages/jest-cli/src/FailedTestsCache.js
+++ b/packages/jest-cli/src/FailedTestsCache.js
@@ -41,8 +41,7 @@ export default class FailedTestsCache {
     if (!this._enabledTestsMap) {
       return globalConfig;
     }
-    // $FlowFixMe Object.assign
-    const newConfig: GlobalConfig = Object.assign({}, globalConfig);
+    const newConfig: GlobalConfig = {...globalConfig};
     newConfig.enabledTestsMap = this._enabledTestsMap;
     return Object.freeze(newConfig);
   }
diff --git a/packages/jest-cli/src/SearchSource.js b/packages/jest-cli/src/SearchSource.js
index 38892285b8d9..1744ef00bb2a 100644
--- a/packages/jest-cli/src/SearchSource.js
+++ b/packages/jest-cli/src/SearchSource.js
@@ -275,10 +275,10 @@ export default class SearchSource {
         filterResult.filtered.map(result => result.test),
       );
 
-      // $FlowFixMe: Object.assign with empty object causes troubles to Flow.
-      return Object.assign({}, searchResult, {
+      return {
+        ...searchResult,
         tests: tests.filter(test => filteredSet.has(test.path)),
-      });
+      };
     }
 
     return searchResult;
diff --git a/packages/jest-cli/src/__tests__/notify_reporter.test.js b/packages/jest-cli/src/__tests__/notify_reporter.test.js
index 26c2b0a59937..424b6f212d1a 100644
--- a/packages/jest-cli/src/__tests__/notify_reporter.test.js
+++ b/packages/jest-cli/src/__tests__/notify_reporter.test.js
@@ -69,11 +69,7 @@ const notifyEvents = [
 ];
 
 test('.addReporter() .removeReporter()', () => {
-  const scheduler = new TestScheduler(
-    {},
-    {},
-    Object.assign({}, initialContext),
-  );
+  const scheduler = new TestScheduler({}, {}, {...initialContext});
   const reporter = new NotifyReporter();
   scheduler.addReporter(reporter);
   expect(scheduler._dispatcher._reporters).toContain(reporter);
diff --git a/packages/jest-cli/src/__tests__/runJestWithCoverage.test.js b/packages/jest-cli/src/__tests__/runJestWithCoverage.test.js
index 75b5949937cc..21a9d76c0c40 100644
--- a/packages/jest-cli/src/__tests__/runJestWithCoverage.test.js
+++ b/packages/jest-cli/src/__tests__/runJestWithCoverage.test.js
@@ -70,13 +70,12 @@ describe('collectCoverageFrom patterns', () => {
   it('should apply collectCoverageFrom patterns coming from SearchSource', async () => {
     expect.assertions(1);
 
-    await runJest(
-      Object.assign({}, defaults, {
-        globalConfig: {
-          rootDir: '',
-        },
-      }),
-    );
+    await runJest({
+      ...defaults,
+      globalConfig: {
+        rootDir: '',
+      },
+    });
     expect(globalConfig.collectCoverageFrom).toEqual([
       'foo.js',
       'dont/cover.js',
@@ -86,29 +85,27 @@ describe('collectCoverageFrom patterns', () => {
   it('excludes coverage from files outside the global collectCoverageFrom config', async () => {
     expect.assertions(1);
 
-    await runJest(
-      Object.assign({}, defaults, {
-        globalConfig: {
-          collectCoverageFrom: ['**/dont/*.js'],
-          rootDir: '',
-        },
-      }),
-    );
+    await runJest({
+      ...defaults,
+      globalConfig: {
+        collectCoverageFrom: ['**/dont/*.js'],
+        rootDir: '',
+      },
+    });
     expect(globalConfig.collectCoverageFrom).toEqual(['dont/cover.js']);
   });
 
   it('respects coveragePathIgnorePatterns', async () => {
     expect.assertions(1);
 
-    await runJest(
-      Object.assign({}, defaults, {
-        globalConfig: {
-          collectCoverageFrom: ['**/*.js'],
-          coveragePathIgnorePatterns: ['dont'],
-          rootDir: '',
-        },
-      }),
-    );
+    await runJest({
+      ...defaults,
+      globalConfig: {
+        collectCoverageFrom: ['**/*.js'],
+        coveragePathIgnorePatterns: ['dont'],
+        rootDir: '',
+      },
+    });
     expect(globalConfig.collectCoverageFrom).toEqual(['foo.js']);
   });
 });
diff --git a/packages/jest-cli/src/__tests__/watch.test.js b/packages/jest-cli/src/__tests__/watch.test.js
index 6ce991334169..8fd2b2926157 100644
--- a/packages/jest-cli/src/__tests__/watch.test.js
+++ b/packages/jest-cli/src/__tests__/watch.test.js
@@ -179,10 +179,11 @@ describe('Watch mode flows', () => {
   it('resolves relative to the package root', () => {
     expect(async () => {
       await watch(
-        Object.assign({}, globalConfig, {
+        {
+          ...globalConfig,
           rootDir: __dirname,
           watchPlugins: [{config: {}, path: watchPluginPath}],
-        }),
+        },
         contexts,
         pipe,
         hasteMapInstances,
@@ -198,13 +199,14 @@ describe('Watch mode flows', () => {
 
     const ci_watch = require('../watch').default;
     ci_watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [
           {config: {}, path: watchPluginPath},
           {config: {}, path: watchPlugin2Path},
         ],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -228,10 +230,11 @@ describe('Watch mode flows', () => {
 
     const ci_watch = require('../watch').default;
     ci_watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -274,10 +277,11 @@ describe('Watch mode flows', () => {
 
     const ci_watch = require('../watch').default;
     ci_watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -308,10 +312,11 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [{config: {}, path: pluginPath}],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -344,10 +349,11 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [{config: {}, path: pluginPath}],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -394,10 +400,11 @@ describe('Watch mode flows', () => {
 
         expect(() => {
           watch(
-            Object.assign({}, globalConfig, {
+            {
+              ...globalConfig,
               rootDir: __dirname,
               watchPlugins: [{config: {}, path: pluginPath}],
-            }),
+            },
             contexts,
             pipe,
             hasteMapInstances,
@@ -441,10 +448,11 @@ describe('Watch mode flows', () => {
         );
 
         watch(
-          Object.assign({}, globalConfig, {
+          {
+            ...globalConfig,
             rootDir: __dirname,
             watchPlugins: [{config: {}, path: pluginPath}],
-          }),
+          },
           contexts,
           pipe,
           hasteMapInstances,
@@ -481,10 +489,11 @@ describe('Watch mode flows', () => {
 
       expect(() => {
         watch(
-          Object.assign({}, globalConfig, {
+          {
+            ...globalConfig,
             rootDir: __dirname,
             watchPlugins: pluginPaths.map(path => ({config: {}, path})),
-          }),
+          },
           contexts,
           pipe,
           hasteMapInstances,
@@ -519,7 +528,8 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [
           {
@@ -527,7 +537,7 @@ describe('Watch mode flows', () => {
             path: pluginPath,
           },
         ],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -552,10 +562,11 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [{config: {}, path: pluginPath}],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -647,10 +658,11 @@ describe('Watch mode flows', () => {
         {virtual: true},
       );
 
-      const config = Object.assign({}, globalConfig, {
+      const config = {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [{config: {}, path: pluginPath}],
-      });
+      };
 
       watch(config, contexts, pipe, hasteMapInstances, stdin);
       await nextTick();
@@ -690,10 +702,11 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [{config: {}, path: pluginPath}],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
@@ -750,13 +763,14 @@ describe('Watch mode flows', () => {
     );
 
     watch(
-      Object.assign({}, globalConfig, {
+      {
+        ...globalConfig,
         rootDir: __dirname,
         watchPlugins: [
           {config: {}, path: pluginPath},
           {config: {}, path: pluginPath2},
         ],
-      }),
+      },
       contexts,
       pipe,
       hasteMapInstances,
diff --git a/packages/jest-cli/src/cli/index.js b/packages/jest-cli/src/cli/index.js
index 709b17305883..031c92d53446 100644
--- a/packages/jest-cli/src/cli/index.js
+++ b/packages/jest-cli/src/cli/index.js
@@ -194,7 +194,7 @@ export const buildArgv = (maybeArgv: ?Argv, project: ?Path) => {
 
   validateCLIOptions(
     argv,
-    Object.assign({}, args.options, {deprecationEntries}),
+    {...args.options, deprecationEntries},
     // strip leading dashes
     Array.isArray(rawArgv)
       ? rawArgv.map(rawArgv => rawArgv.replace(/^--?/, ''))
diff --git a/packages/jest-cli/src/lib/update_global_config.js b/packages/jest-cli/src/lib/update_global_config.js
index ec782b5032bd..5b0047f8a6b1 100644
--- a/packages/jest-cli/src/lib/update_global_config.js
+++ b/packages/jest-cli/src/lib/update_global_config.js
@@ -36,8 +36,7 @@ export type Options = {
 };
 
 export default (globalConfig: GlobalConfig, options: Options): GlobalConfig => {
-  // $FlowFixMe Object.assign
-  const newConfig: GlobalConfig = Object.assign({}, globalConfig);
+  const newConfig: GlobalConfig = {...globalConfig};
 
   if (!options) {
     options = {};
diff --git a/packages/jest-cli/src/reporters/__tests__/coverage_reporter.test.js b/packages/jest-cli/src/reporters/__tests__/coverage_reporter.test.js
index a1087b137dbf..a93b1cc71749 100644
--- a/packages/jest-cli/src/reporters/__tests__/coverage_reporter.test.js
+++ b/packages/jest-cli/src/reporters/__tests__/coverage_reporter.test.js
@@ -95,7 +95,7 @@ describe('onRunComplete', () => {
       ].reduce((c, f) => {
         const file = path.resolve(f[0]);
         const override = f[1];
-        const obj = Object.assign({}, covSummary, override);
+        const obj = {...covSummary, ...override};
         c[file] = libCoverage.createCoverageSummary(obj);
         return c;
       }, {});
diff --git a/packages/jest-cli/src/reporters/__tests__/summary_reporter.test.js b/packages/jest-cli/src/reporters/__tests__/summary_reporter.test.js
index 799a4c41f9c6..be5144991d25 100644
--- a/packages/jest-cli/src/reporters/__tests__/summary_reporter.test.js
+++ b/packages/jest-cli/src/reporters/__tests__/summary_reporter.test.js
@@ -8,7 +8,7 @@
 
 import SummaryReporter from '../summary_reporter';
 
-const env = Object.assign({}, process.env);
+const env = {...process.env};
 const now = Date.now;
 const write = process.stderr.write;
 const globalConfig = {
diff --git a/packages/jest-cli/src/runJest.js b/packages/jest-cli/src/runJest.js
index d7660791f418..8e3a6dcb1785 100644
--- a/packages/jest-cli/src/runJest.js
+++ b/packages/jest-cli/src/runJest.js
@@ -192,10 +192,7 @@ export default (async function runJest({
   );
 
   if (collectCoverageFrom.length) {
-    // $FlowFixMe Object.assign
-    const newConfig: GlobalConfig = Object.assign({}, globalConfig, {
-      collectCoverageFrom,
-    });
+    const newConfig: GlobalConfig = {...globalConfig, collectCoverageFrom};
     globalConfig = Object.freeze(newConfig);
   }
 
diff --git a/packages/jest-config/src/normalize.js b/packages/jest-config/src/normalize.js
index e820158e1157..7c08a098c013 100644
--- a/packages/jest-config/src/normalize.js
+++ b/packages/jest-config/src/normalize.js
@@ -59,12 +59,11 @@ const mergeOptionWithPreset = (
   optionName: string,
 ) => {
   if (options[optionName] && preset[optionName]) {
-    options[optionName] = Object.assign(
-      {},
-      options[optionName],
-      preset[optionName],
-      options[optionName],
-    );
+    options[optionName] = {
+      ...options[optionName],
+      ...preset[optionName],
+      ...options[optionName],
+    };
   }
 };
 
@@ -127,7 +126,7 @@ const setupPreset = (
   mergeOptionWithPreset(options, preset, 'moduleNameMapper');
   mergeOptionWithPreset(options, preset, 'transform');
 
-  return Object.assign({}, preset, options);
+  return {...preset, ...options};
 };
 
 const setupBabelJest = (options: InitialOptions) => {
@@ -447,9 +446,9 @@ export default function normalize(options: InitialOptions, argv: Argv) {
   }
 
   const babelJest = setupBabelJest(options);
-  const newOptions: $Shape<
-    DefaultOptions & ProjectConfig & GlobalConfig,
-  > = (Object.assign({}, DEFAULT_CONFIG): any);
+  const newOptions: $Shape<DefaultOptions & ProjectConfig & GlobalConfig> = {
+    ...DEFAULT_CONFIG,
+  };
 
   try {
     // try to resolve windows short paths, ignoring errors (permission errors, mostly)
@@ -580,7 +579,7 @@ export default function normalize(options: InitialOptions, argv: Argv) {
         value = normalizeUnmockedModulePathPatterns(options, key);
         break;
       case 'haste':
-        value = Object.assign({}, options[key]);
+        value = {...options[key]};
         if (value.hasteImplModulePath != null) {
           value.hasteImplModulePath = resolve(newOptions.resolver, {
             filePath: replaceRootDirInPath(
diff --git a/packages/jest-config/src/setFromArgv.js b/packages/jest-config/src/setFromArgv.js
index 45facad681e6..2cde2ee37d33 100644
--- a/packages/jest-config/src/setFromArgv.js
+++ b/packages/jest-config/src/setFromArgv.js
@@ -52,10 +52,9 @@ export default function setFromArgv(
       return options;
     }, {});
 
-  return Object.assign(
-    {},
-    options,
-    isJSONString(argv.config) ? JSON.parse(argv.config) : null,
-    argvToOptions,
-  );
+  return {
+    ...options,
+    ...(isJSONString(argv.config) ? JSON.parse(argv.config) : null),
+    ...argvToOptions,
+  };
 }
diff --git a/packages/jest-diff/src/index.js b/packages/jest-diff/src/index.js
index 60dfc1d97137..716e863fb1c4 100644
--- a/packages/jest-diff/src/index.js
+++ b/packages/jest-diff/src/index.js
@@ -35,17 +35,13 @@ const PLUGINS = [
 const FORMAT_OPTIONS = {
   plugins: PLUGINS,
 };
-const FORMAT_OPTIONS_0 = Object.assign({}, FORMAT_OPTIONS, {
-  indent: 0,
-});
+const FORMAT_OPTIONS_0 = {...FORMAT_OPTIONS, indent: 0};
 const FALLBACK_FORMAT_OPTIONS = {
   callToJSON: false,
   maxDepth: 10,
   plugins: PLUGINS,
 };
-const FALLBACK_FORMAT_OPTIONS_0 = Object.assign({}, FALLBACK_FORMAT_OPTIONS, {
-  indent: 0,
-});
+const FALLBACK_FORMAT_OPTIONS_0 = {...FALLBACK_FORMAT_OPTIONS, indent: 0};
 
 // Generate a string that will highlight the difference between two values
 // with green and red. (similar to how github does code diffing)
diff --git a/packages/jest-each/src/bind.js b/packages/jest-each/src/bind.js
index c8b5c019872e..76e646a0cad3 100644
--- a/packages/jest-each/src/bind.js
+++ b/packages/jest-each/src/bind.js
@@ -184,7 +184,7 @@ const buildTable = (
     .map((_, index) => data.slice(index * rowSize, index * rowSize + rowSize))
     .map(row =>
       row.reduce(
-        (acc, value, index) => Object.assign({}, acc, {[keys[index]]: value}),
+        (acc, value, index) => Object.assign(acc, {[keys[index]]: value}),
         {},
       ),
     );
diff --git a/packages/jest-environment-jsdom/src/__mocks__/index.js b/packages/jest-environment-jsdom/src/__mocks__/index.js
index 8f868074616b..f2bf9a30476e 100644
--- a/packages/jest-environment-jsdom/src/__mocks__/index.js
+++ b/packages/jest-environment-jsdom/src/__mocks__/index.js
@@ -16,7 +16,7 @@ JSDOMEnvironment.mockImplementation(function(config) {
     console: {},
   };
 
-  const globalValues = Object.assign({}, config.globals);
+  const globalValues = {...config.globals};
   for (const customGlobalKey in globalValues) {
     this.global[customGlobalKey] = globalValues[customGlobalKey];
   }
diff --git a/packages/jest-environment-jsdom/src/index.js b/packages/jest-environment-jsdom/src/index.js
index 9b19f6fb38a7..52eed2ff069c 100644
--- a/packages/jest-environment-jsdom/src/index.js
+++ b/packages/jest-environment-jsdom/src/index.js
@@ -24,20 +24,13 @@ class JSDOMEnvironment {
   moduleMocker: ?ModuleMocker;
 
   constructor(config: ProjectConfig, options?: EnvironmentContext = {}) {
-    this.dom = new JSDOM(
-      '<!DOCTYPE html>',
-      Object.assign(
-        {
-          pretendToBeVisual: true,
-          runScripts: 'dangerously',
-          url: config.testURL,
-          virtualConsole: new VirtualConsole().sendTo(
-            options.console || console,
-          ),
-        },
-        config.testEnvironmentOptions,
-      ),
-    );
+    this.dom = new JSDOM('<!DOCTYPE html>', {
+      pretendToBeVisual: true,
+      runScripts: 'dangerously',
+      url: config.testURL,
+      virtualConsole: new VirtualConsole().sendTo(options.console || console),
+      ...config.testEnvironmentOptions,
+    });
     const global = (this.global = this.dom.window.document.defaultView);
     // Node's error-message stack size is limited at 10, but it's pretty useful
     // to see more than that when a test fails.
diff --git a/packages/jest-haste-map/src/__tests__/index.test.js b/packages/jest-haste-map/src/__tests__/index.test.js
index cdf7a88df62a..7e23749f3d93 100644
--- a/packages/jest-haste-map/src/__tests__/index.test.js
+++ b/packages/jest-haste-map/src/__tests__/index.test.js
@@ -223,12 +223,8 @@ describe('HasteMap', () => {
   it('creates different cache file paths for different roots', () => {
     jest.resetModuleRegistry();
     const HasteMap = require('../');
-    const hasteMap1 = new HasteMap(
-      Object.assign({}, defaultConfig, {rootDir: '/root1'}),
-    );
-    const hasteMap2 = new HasteMap(
-      Object.assign({}, defaultConfig, {rootDir: '/root2'}),
-    );
+    const hasteMap1 = new HasteMap({...defaultConfig, rootDir: '/root1'});
+    const hasteMap2 = new HasteMap({...defaultConfig, rootDir: '/root2'});
     expect(hasteMap1.getCacheFilePath()).not.toBe(hasteMap2.getCacheFilePath());
   });
 
@@ -236,9 +232,10 @@ describe('HasteMap', () => {
     jest.resetModuleRegistry();
     const HasteMap = require('../');
     const dependencyExtractor = require('./dependencyExtractor');
-    const config = Object.assign({}, defaultConfig, {
+    const config = {
+      ...defaultConfig,
       dependencyExtractor: require.resolve('./dependencyExtractor'),
-    });
+    };
     dependencyExtractor.setCacheKey('foo');
     const hasteMap1 = new HasteMap(config);
     dependencyExtractor.setCacheKey('bar');
@@ -260,12 +257,8 @@ describe('HasteMap', () => {
   it('creates different cache file paths for different projects', () => {
     jest.resetModuleRegistry();
     const HasteMap = require('../');
-    const hasteMap1 = new HasteMap(
-      Object.assign({}, defaultConfig, {name: '@scoped/package'}),
-    );
-    const hasteMap2 = new HasteMap(
-      Object.assign({}, defaultConfig, {name: '-scoped-package'}),
-    );
+    const hasteMap1 = new HasteMap({...defaultConfig, name: '@scoped/package'});
+    const hasteMap2 = new HasteMap({...defaultConfig, name: '-scoped-package'});
     expect(hasteMap1.getCacheFilePath()).not.toBe(hasteMap2.getCacheFilePath());
   });
 
@@ -284,7 +277,7 @@ describe('HasteMap', () => {
     }));
 
   it('ignores files given a pattern', () => {
-    const config = Object.assign({}, defaultConfig, {ignorePattern: /Kiwi/});
+    const config = {...defaultConfig, ignorePattern: /Kiwi/};
     mockFs['/project/fruits/Kiwi.js'] = `
       // Kiwi!
     `;
@@ -325,12 +318,11 @@ describe('HasteMap', () => {
       // fbjs2
     `;
 
-    const hasteMap = new HasteMap(
-      Object.assign({}, defaultConfig, {
-        mocksPattern: '/__mocks__/',
-        providesModuleNodeModules: ['react', 'fbjs'],
-      }),
-    );
+    const hasteMap = new HasteMap({
+      ...defaultConfig,
+      mocksPattern: '/__mocks__/',
+      providesModuleNodeModules: ['react', 'fbjs'],
+    });
 
     return hasteMap.build().then(({__hasteMapForTest: data}) => {
       expect(data.clocks).toEqual(mockClocks);
@@ -424,13 +416,12 @@ describe('HasteMap', () => {
           return Promise.resolve(data);
         });
 
-        const hasteMap = new HasteMap(
-          Object.assign({}, defaultConfig, {
-            computeSha1: true,
-            maxWorkers: 1,
-            useWatchman,
-          }),
-        );
+        const hasteMap = new HasteMap({
+          ...defaultConfig,
+          computeSha1: true,
+          maxWorkers: 1,
+          useWatchman,
+        });
 
         const data = (await hasteMap.build()).__hasteMapForTest;
 
@@ -489,12 +480,11 @@ describe('HasteMap', () => {
       module.exports = require("./video.mp4");
     `;
 
-    const hasteMap = new HasteMap(
-      Object.assign({}, defaultConfig, {
-        extensions: [...defaultConfig.extensions],
-        roots: [...defaultConfig.roots, '/project/video'],
-      }),
-    );
+    const hasteMap = new HasteMap({
+      ...defaultConfig,
+      extensions: [...defaultConfig.extensions],
+      roots: [...defaultConfig.roots, '/project/video'],
+    });
 
     const {__hasteMapForTest: data} = await hasteMap.build();
 
@@ -508,12 +498,11 @@ describe('HasteMap', () => {
       // fbjs!
     `;
 
-    const hasteMap = new HasteMap(
-      Object.assign({}, defaultConfig, {
-        mocksPattern: '/__mocks__/',
-        retainAllFiles: true,
-      }),
-    );
+    const hasteMap = new HasteMap({
+      ...defaultConfig,
+      mocksPattern: '/__mocks__/',
+      retainAllFiles: true,
+    });
 
     return hasteMap.build().then(({__hasteMapForTest: data}) => {
       // Expect the node module to be part of files but make sure it wasn't
@@ -543,9 +532,7 @@ describe('HasteMap', () => {
       // Blueberry too!
     `;
 
-    return new HasteMap(
-      Object.assign({mocksPattern: '__mocks__'}, defaultConfig),
-    )
+    return new HasteMap({mocksPattern: '__mocks__', ...defaultConfig})
       .build()
       .then(({__hasteMapForTest: data}) => {
         expect(console.warn.mock.calls[0][0]).toMatchSnapshot();
@@ -588,9 +575,7 @@ describe('HasteMap', () => {
       const Banana = require("Banana");
     `;
 
-    return new HasteMap(
-      Object.assign({throwOnModuleCollision: true}, defaultConfig),
-    )
+    return new HasteMap({throwOnModuleCollision: true, ...defaultConfig})
       .build()
       .catch(err => {
         expect(err).toMatchSnapshot();
@@ -970,9 +955,7 @@ describe('HasteMap', () => {
         vegetables: 'c:fake-clock:4',
       });
 
-      const config = Object.assign({}, defaultConfig, {
-        ignorePattern: /Kiwi|Pear/,
-      });
+      const config = {...defaultConfig, ignorePattern: /Kiwi|Pear/};
       return new HasteMap(config).build().then(({moduleMap}) => {
         expect(moduleMap.getModule('Pear')).toBe(null);
       });
@@ -1004,13 +987,12 @@ describe('HasteMap', () => {
     const jestWorker = require('jest-worker');
     const path = require('path');
     const dependencyExtractor = path.join(__dirname, 'dependencyExtractor.js');
-    return new HasteMap(
-      Object.assign({}, defaultConfig, {
-        dependencyExtractor,
-        hasteImplModulePath: undefined,
-        maxWorkers: 4,
-      }),
-    )
+    return new HasteMap({
+      ...defaultConfig,
+      dependencyExtractor,
+      hasteImplModulePath: undefined,
+      maxWorkers: 4,
+    })
       .build()
       .then(({__hasteMapForTest: data}) => {
         expect(jestWorker.mock.calls.length).toBe(1);
@@ -1176,7 +1158,7 @@ describe('HasteMap', () => {
         if (options.mockFs) {
           mockFs = options.mockFs;
         }
-        const watchConfig = Object.assign({}, defaultConfig, {watch: true});
+        const watchConfig = {...defaultConfig, watch: true};
         const hm = new HasteMap(watchConfig);
         await hm.build();
         try {
diff --git a/packages/jest-jasmine2/src/jasmine/jasmineLight.js b/packages/jest-jasmine2/src/jasmine/jasmineLight.js
index 2004ad36c30f..341e4c211647 100644
--- a/packages/jest-jasmine2/src/jasmine/jasmineLight.js
+++ b/packages/jest-jasmine2/src/jasmine/jasmineLight.js
@@ -43,7 +43,7 @@ import Suite from './Suite';
 import Timer from './Timer';
 
 exports.create = function(createOptions: Object) {
-  const j$ = Object.assign({}, createOptions);
+  const j$ = {...createOptions};
 
   j$._DEFAULT_TIMEOUT_INTERVAL = 5000;
 
diff --git a/packages/jest-jasmine2/src/jasmine/spyRegistry.js b/packages/jest-jasmine2/src/jasmine/spyRegistry.js
index cba5c7d7daa3..b3e84c09cad2 100644
--- a/packages/jest-jasmine2/src/jasmine/spyRegistry.js
+++ b/packages/jest-jasmine2/src/jasmine/spyRegistry.js
@@ -200,9 +200,7 @@ export default function SpyRegistry(options: Object) {
       restoreObjectToOriginalState: restoreStrategy,
     });
 
-    const spiedDescriptor = Object.assign({}, descriptor, {
-      [accessType]: spiedProperty,
-    });
+    const spiedDescriptor = {...descriptor, [accessType]: spiedProperty};
 
     Object.defineProperty(obj, propertyName, spiedDescriptor);
 
diff --git a/packages/jest-phabricator/src/index.js b/packages/jest-phabricator/src/index.js
index 16995e0ed0e4..5c02ee4ae1b3 100644
--- a/packages/jest-phabricator/src/index.js
+++ b/packages/jest-phabricator/src/index.js
@@ -43,7 +43,8 @@ function summarize(coverageMap: CoverageMap) {
 
 module.exports = function(results: AggregatedResult): PhabricatorReport {
   // $FlowFixMe: This should work, but it does not.
-  return Object.assign({}, results, {
+  return {
+    ...results,
     coverageMap: results.coverageMap && summarize(results.coverageMap),
-  });
+  };
 };
diff --git a/packages/jest-repl/src/cli/args.js b/packages/jest-repl/src/cli/args.js
index 242eb2928f46..c5d29b013765 100644
--- a/packages/jest-repl/src/cli/args.js
+++ b/packages/jest-repl/src/cli/args.js
@@ -11,7 +11,8 @@ import Runtime from 'jest-runtime';
 
 export const usage = 'Usage: $0 [--config=<pathToConfigFile>]';
 
-export const options = Object.assign({}, Runtime.getCLIOptions(), {
+export const options = {
+  ...Runtime.getCLIOptions(),
   replname: {
     alias: 'r',
     description:
@@ -19,4 +20,4 @@ export const options = Object.assign({}, Runtime.getCLIOptions(), {
       'transformed. For example, "repl.ts" if using a TypeScript transformer.',
     type: 'string',
   },
-});
+};
diff --git a/packages/jest-repl/src/cli/index.js b/packages/jest-repl/src/cli/index.js
index 6e10194437ca..b9a0abaf9c3b 100644
--- a/packages/jest-repl/src/cli/index.js
+++ b/packages/jest-repl/src/cli/index.js
@@ -22,10 +22,7 @@ const REPL_SCRIPT = path.resolve(__dirname, './repl.js');
 module.exports = function() {
   const argv = yargs.usage(args.usage).options(args.options).argv;
 
-  validateCLIOptions(
-    argv,
-    Object.assign({}, args.options, {deprecationEntries}),
-  );
+  validateCLIOptions(argv, {...args.options, deprecationEntries});
 
   argv._ = [REPL_SCRIPT];
 
diff --git a/packages/jest-runner/src/runTest.js b/packages/jest-runner/src/runTest.js
index d388d1c427e0..14d34483955a 100644
--- a/packages/jest-runner/src/runTest.js
+++ b/packages/jest-runner/src/runTest.js
@@ -56,12 +56,11 @@ async function runTestInternal(
   let testEnvironment = config.testEnvironment;
 
   if (customEnvironment) {
-    testEnvironment = getTestEnvironment(
-      Object.assign({}, config, {
-        // $FlowFixMe
-        testEnvironment: customEnvironment,
-      }),
-    );
+    testEnvironment = getTestEnvironment({
+      ...config,
+      // $FlowFixMe
+      testEnvironment: customEnvironment,
+    });
   }
 
   /* $FlowFixMe */
diff --git a/packages/jest-runtime/src/__mocks__/createRuntime.js b/packages/jest-runtime/src/__mocks__/createRuntime.js
index ae951f28cbec..0a2932e87176 100644
--- a/packages/jest-runtime/src/__mocks__/createRuntime.js
+++ b/packages/jest-runtime/src/__mocks__/createRuntime.js
@@ -14,25 +14,24 @@ module.exports = function createRuntime(filename, config) {
   const {normalize} = require('jest-config');
 
   config = normalize(
-    Object.assign(
-      {
-        haste: {
-          hasteImplModulePath: path.resolve(
-            __dirname,
-            '..',
-            '..',
-            '..',
-            'jest-haste-map',
-            'src',
-            '__tests__',
-            'haste_impl.js',
-          ),
-        },
-        name: 'Runtime-' + filename.replace(/\W/, '-') + '.tests',
-        rootDir: path.resolve(path.dirname(filename), 'test_root'),
+    {
+      haste: {
+        hasteImplModulePath: path.resolve(
+          __dirname,
+          '..',
+          '..',
+          '..',
+          'jest-haste-map',
+          'src',
+          '__tests__',
+          'haste_impl.js',
+        ),
       },
-      config,
-    ),
+      name: 'Runtime-' + filename.replace(/\W/, '-') + '.tests',
+      rootDir: path.resolve(path.dirname(filename), 'test_root'),
+      ...config,
+    },
+
     {},
   ).options;
 
diff --git a/packages/jest-runtime/src/__tests__/script_transformer.test.js b/packages/jest-runtime/src/__tests__/script_transformer.test.js
index 6aa2094c670c..63dcf0f420fb 100644
--- a/packages/jest-runtime/src/__tests__/script_transformer.test.js
+++ b/packages/jest-runtime/src/__tests__/script_transformer.test.js
@@ -11,7 +11,8 @@
 jest
   .mock('fs', () =>
     // Node 10.5.x compatibility
-    Object.assign({}, jest.genMockFromModule('fs'), {
+    ({
+      ...jest.genMockFromModule('fs'),
       ReadStream: jest.requireActual('fs').ReadStream,
       WriteStream: jest.requireActual('fs').WriteStream,
       readFileSync: jest.fn((path, options) => {
@@ -264,9 +265,10 @@ describe('ScriptTransformer', () => {
     "throws an error if `process` doesn't return a string or an object" +
       'containing `code` key with processed string',
     () => {
-      config = Object.assign(config, {
+      config = {
+        ...config,
         transform: [['^.+\\.js$', 'passthrough-preprocessor']],
-      });
+      };
       const scriptTransformer = new ScriptTransformer(config);
 
       const incorrectReturnValues = [
@@ -299,9 +301,10 @@ describe('ScriptTransformer', () => {
   );
 
   it("throws an error if `process` doesn't defined", () => {
-    Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'skipped-required-props-preprocessor']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
     expect(() =>
       scriptTransformer.transformSource('sample.js', '', false),
@@ -309,11 +312,12 @@ describe('ScriptTransformer', () => {
   });
 
   it('throws an error if createTransformer returns object without `process` method', () => {
-    Object.assign(config, {
+    config = {
+      ...config,
       transform: [
         ['^.+\\.js$', 'skipped-required-create-transformer-props-preprocessor'],
       ],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
     expect(() =>
       scriptTransformer.transformSource('sample.js', '', false),
@@ -321,9 +325,10 @@ describe('ScriptTransformer', () => {
   });
 
   it("shouldn't throw error without process method. But with corrent createTransformer method", () => {
-    Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'skipped-process-method-preprocessor']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
     expect(() =>
       scriptTransformer.transformSource('sample.js', '', false),
@@ -331,9 +336,7 @@ describe('ScriptTransformer', () => {
   });
 
   it('uses the supplied preprocessor', () => {
-    config = Object.assign(config, {
-      transform: [['^.+\\.js$', 'test_preprocessor']],
-    });
+    config = {...config, transform: [['^.+\\.js$', 'test_preprocessor']]};
     const scriptTransformer = new ScriptTransformer(config);
     scriptTransformer.transform('/fruits/banana.js', {});
 
@@ -347,12 +350,13 @@ describe('ScriptTransformer', () => {
   });
 
   it('uses multiple preprocessors', () => {
-    config = Object.assign(config, {
+    config = {
+      ...config,
       transform: [
         ['^.+\\.js$', 'test_preprocessor'],
         ['^.+\\.css$', 'css-preprocessor'],
       ],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
 
     scriptTransformer.transform('/fruits/banana.js', {});
@@ -369,9 +373,10 @@ describe('ScriptTransformer', () => {
   });
 
   it('writes source map if preprocessor supplies it', () => {
-    config = Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
 
     const map = {
@@ -395,9 +400,10 @@ describe('ScriptTransformer', () => {
   });
 
   it('writes source map if preprocessor inlines it', () => {
-    config = Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
 
     const sourceMap = JSON.stringify({
@@ -424,9 +430,10 @@ describe('ScriptTransformer', () => {
   });
 
   it('writes source maps if given by the transformer', () => {
-    config = Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
 
     const map = {
@@ -453,9 +460,10 @@ describe('ScriptTransformer', () => {
   });
 
   it('does not write source map if not given by the transformer', () => {
-    config = Object.assign(config, {
+    config = {
+      ...config,
       transform: [['^.+\\.js$', 'preprocessor-with-sourcemaps']],
-    });
+    };
     const scriptTransformer = new ScriptTransformer(config);
 
     require('preprocessor-with-sourcemaps').process.mockReturnValue({
@@ -471,9 +479,7 @@ describe('ScriptTransformer', () => {
   });
 
   it('passes expected transform options to getCacheKey', () => {
-    config = Object.assign(config, {
-      transform: [['^.+\\.js$', 'test_preprocessor']],
-    });
+    config = {...config, transform: [['^.+\\.js$', 'test_preprocessor']]};
     const scriptTransformer = new ScriptTransformer(config);
 
     scriptTransformer.transform('/fruits/banana.js', {
@@ -485,9 +491,10 @@ describe('ScriptTransformer', () => {
   });
 
   it('reads values from the cache', () => {
-    const transformConfig = Object.assign(config, {
+    const transformConfig = {
+      ...config,
       transform: [['^.+\\.js$', 'test_preprocessor']],
-    });
+    };
     let scriptTransformer = new ScriptTransformer(transformConfig);
     scriptTransformer.transform('/fruits/banana.js', {});
 
@@ -525,19 +532,17 @@ describe('ScriptTransformer', () => {
   });
 
   it('does not reuse the in-memory cache between different projects', () => {
-    const scriptTransformer = new ScriptTransformer(
-      Object.assign({}, config, {
-        transform: [['^.+\\.js$', 'test_preprocessor']],
-      }),
-    );
+    const scriptTransformer = new ScriptTransformer({
+      ...config,
+      transform: [['^.+\\.js$', 'test_preprocessor']],
+    });
 
     scriptTransformer.transform('/fruits/banana.js', {});
 
-    const anotherScriptTransformer = new ScriptTransformer(
-      Object.assign({}, config, {
-        transform: [['^.+\\.js$', 'css-preprocessor']],
-      }),
-    );
+    const anotherScriptTransformer = new ScriptTransformer({
+      ...config,
+      transform: [['^.+\\.js$', 'css-preprocessor']],
+    });
 
     anotherScriptTransformer.transform('/fruits/banana.js', {});
 
diff --git a/packages/jest-runtime/src/cli/index.js b/packages/jest-runtime/src/cli/index.js
index fbc3ed4ec8ef..2662efe5407b 100644
--- a/packages/jest-runtime/src/cli/index.js
+++ b/packages/jest-runtime/src/cli/index.js
@@ -37,10 +37,7 @@ export function run(cliArgv?: Argv, cliInfo?: Array<string>) {
       .version(false)
       .options(args.options).argv;
 
-    validateCLIOptions(
-      argv,
-      Object.assign({}, args.options, {deprecationEntries}),
-    );
+    validateCLIOptions(argv, {...args.options, deprecationEntries});
   }
 
   if (argv.help) {
@@ -70,10 +67,11 @@ export function run(cliArgv?: Argv, cliInfo?: Array<string>) {
   const options = readConfig(argv, root);
   const globalConfig = options.globalConfig;
   // Always disable automocking in scripts.
-  const config = Object.assign({}, options.projectConfig, {
+  const config = {
+    ...options.projectConfig,
     automock: false,
     unmockedModulePathPatterns: null,
-  });
+  };
 
   // Break circular dependency
   const Runtime = require('..');
diff --git a/packages/jest-snapshot/src/__mocks__/prettier.js b/packages/jest-snapshot/src/__mocks__/prettier.js
index a450b76e0b34..717891860829 100644
--- a/packages/jest-snapshot/src/__mocks__/prettier.js
+++ b/packages/jest-snapshot/src/__mocks__/prettier.js
@@ -4,17 +4,10 @@ const prettier = jest.requireActual('prettier');
 
 module.exports = {
   format: (text, opts) =>
-    prettier.format(
-      text,
-      Object.assign(
-        {
-          pluginSearchDirs: [
-            require('path').dirname(require.resolve('prettier')),
-          ],
-        },
-        opts,
-      ),
-    ),
+    prettier.format(text, {
+      pluginSearchDirs: [require('path').dirname(require.resolve('prettier'))],
+      ...opts,
+    }),
   getFileInfo: {sync: () => ({inferredParser: 'babylon'})},
   resolveConfig: {sync: jest.fn()},
   version: prettier.version,
diff --git a/packages/jest-snapshot/src/inline_snapshots.js b/packages/jest-snapshot/src/inline_snapshots.js
index 469c7bd8f3d7..cd171877a4a7 100644
--- a/packages/jest-snapshot/src/inline_snapshots.js
+++ b/packages/jest-snapshot/src/inline_snapshots.js
@@ -75,13 +75,11 @@ const saveSnapshotsForFile = (
     : (config && config.parser) || simpleDetectParser(sourceFilePath);
 
   // Format the source code using the custom parser API.
-  const newSourceFile = prettier.format(
-    sourceFile,
-    Object.assign({}, config, {
-      filepath: sourceFilePath,
-      parser: createParser(snapshots, inferredParser, babelTraverse),
-    }),
-  );
+  const newSourceFile = prettier.format(sourceFile, {
+    ...config,
+    filepath: sourceFilePath,
+    parser: createParser(snapshots, inferredParser, babelTraverse),
+  });
 
   if (newSourceFile !== sourceFile) {
     fs.writeFileSync(sourceFilePath, newSourceFile);
@@ -93,9 +91,7 @@ const groupSnapshotsBy = (createKey: InlineSnapshot => string) => (
 ) =>
   snapshots.reduce((object, inlineSnapshot) => {
     const key = createKey(inlineSnapshot);
-    return Object.assign(object, {
-      [key]: (object[key] || []).concat(inlineSnapshot),
-    });
+    return {...object, [key]: (object[key] || []).concat(inlineSnapshot)};
   }, {});
 
 const groupSnapshotsByFrame = groupSnapshotsBy(
diff --git a/packages/jest-snapshot/src/utils.js b/packages/jest-snapshot/src/utils.js
index 950a7d17ab40..61b812ebdf68 100644
--- a/packages/jest-snapshot/src/utils.js
+++ b/packages/jest-snapshot/src/utils.js
@@ -179,7 +179,7 @@ export const saveSnapshotFile = (
 };
 
 export const deepMerge = (target: any, source: any) => {
-  const mergedOutput = Object.assign({}, target);
+  const mergedOutput = {...target};
   if (isObject(target) && isObject(source)) {
     Object.keys(source).forEach(key => {
       if (isObject(source[key]) && !source[key].$$typeof) {
diff --git a/packages/jest-util/src/FakeTimers.js b/packages/jest-util/src/FakeTimers.js
index 5352ec71fb36..8fe11e83295d 100644
--- a/packages/jest-util/src/FakeTimers.js
+++ b/packages/jest-util/src/FakeTimers.js
@@ -239,7 +239,7 @@ export default class FakeTimers<TimerRef> {
   }
 
   runOnlyPendingTimers() {
-    const timers = Object.assign({}, this._timers);
+    const timers = {...this._timers};
     this._checkFakeTimers();
     this._immediates.forEach(this._runImmediate, this);
     Object.keys(timers)
diff --git a/packages/jest-util/src/__tests__/getCallsite.test.js b/packages/jest-util/src/__tests__/getCallsite.test.js
index ab04ebf66241..d73c7c80dfae 100644
--- a/packages/jest-util/src/__tests__/getCallsite.test.js
+++ b/packages/jest-util/src/__tests__/getCallsite.test.js
@@ -5,12 +5,11 @@ import SourceMap from 'source-map';
 import getCallsite from '../getCallsite';
 
 // Node 10.5.x compatibility
-jest.mock('fs', () =>
-  Object.assign({}, jest.genMockFromModule('fs'), {
-    ReadStream: jest.requireActual('fs').ReadStream,
-    WriteStream: jest.requireActual('fs').WriteStream,
-  }),
-);
+jest.mock('fs', () => ({
+  ...jest.genMockFromModule('fs'),
+  ReadStream: jest.requireActual('fs').ReadStream,
+  WriteStream: jest.requireActual('fs').WriteStream,
+}));
 
 describe('getCallsite', () => {
   test('without source map', () => {
diff --git a/packages/jest-validate/src/validate.js b/packages/jest-validate/src/validate.js
index af64a7a9dfcd..0495b5990774 100644
--- a/packages/jest-validate/src/validate.js
+++ b/packages/jest-validate/src/validate.js
@@ -87,13 +87,12 @@ const validate = (config: Object, options: ValidationOptions) => {
     options.recursiveBlacklist || [],
   );
 
-  const defaultedOptions: ValidationOptions = Object.assign(
-    {},
-    defaultConfig,
-    options,
-    {recursiveBlacklist: combinedBlacklist},
-    {title: Object.assign({}, defaultConfig.title, options.title)},
-  );
+  const defaultedOptions: ValidationOptions = Object.assign({
+    ...defaultConfig,
+    ...options,
+    recursiveBlacklist: combinedBlacklist,
+    title: options.title || defaultConfig.title,
+  });
 
   const {hasDeprecationWarnings: hdw} = _validate(
     config,
diff --git a/packages/jest-validate/src/validateCLIOptions.js b/packages/jest-validate/src/validateCLIOptions.js
index 7ac3677b2381..faf863efc9a2 100644
--- a/packages/jest-validate/src/validateCLIOptions.js
+++ b/packages/jest-validate/src/validateCLIOptions.js
@@ -55,14 +55,10 @@ const logDeprecatedOptions = (
   argv: Argv,
 ) => {
   deprecatedOptions.forEach(opt => {
-    deprecationWarning(
-      argv,
-      opt,
-      deprecationEntries,
-      Object.assign({}, defaultConfig, {
-        comment: DOCUMENTATION_NOTE,
-      }),
-    );
+    deprecationWarning(argv, opt, deprecationEntries, {
+      ...defaultConfig,
+      comment: DOCUMENTATION_NOTE,
+    });
   });
 };
 
diff --git a/packages/jest-worker/src/index.js b/packages/jest-worker/src/index.js
index 807545c1a634..b5bc4885b53f 100644
--- a/packages/jest-worker/src/index.js
+++ b/packages/jest-worker/src/index.js
@@ -74,7 +74,7 @@ export default class JestWorker {
   _workerPool: WorkerPoolInterface;
 
   constructor(workerPath: string, options?: FarmOptions) {
-    this._options = Object.assign({}, options);
+    this._options = {...options};
 
     const workerPoolOptions: WorkerPoolOptions = {
       forkOptions: this._options.forkOptions || {},
diff --git a/packages/jest-worker/src/workers/ChildProcessWorker.js b/packages/jest-worker/src/workers/ChildProcessWorker.js
index 49b86a0b9caf..2ad70be2cd07 100644
--- a/packages/jest-worker/src/workers/ChildProcessWorker.js
+++ b/packages/jest-worker/src/workers/ChildProcessWorker.js
@@ -57,27 +57,18 @@ export default class ChildProcessWorker implements WorkerInterface {
 
   initialize() {
     const forceColor = supportsColor.stdout ? {FORCE_COLOR: '1'} : {};
-    const child = childProcess.fork(
-      require.resolve('./processChild'),
-      // $FlowFixMe: Flow does not work well with Object.assign.
-      Object.assign(
-        {
-          cwd: process.cwd(),
-          env: Object.assign(
-            {},
-            process.env,
-            {
-              JEST_WORKER_ID: this._options.workerId,
-            },
-            forceColor,
-          ),
-          // Suppress --debug / --inspect flags while preserving others (like --harmony).
-          execArgv: process.execArgv.filter(v => !/^--(debug|inspect)/.test(v)),
-          silent: true,
-        },
-        this._options.forkOptions,
-      ),
-    );
+    const child = childProcess.fork(require.resolve('./processChild'), {
+      cwd: process.cwd(),
+      env: {
+        ...process.env,
+        JEST_WORKER_ID: this._options.workerId,
+        ...forceColor,
+      },
+      // Suppress --debug / --inspect flags while preserving others (like --harmony).
+      execArgv: process.execArgv.filter(v => !/^--(debug|inspect)/.test(v)),
+      silent: true,
+      ...this._options.forkOptions,
+    });
 
     child.on('message', this.onMessage.bind(this));
     child.on('exit', this.onExit.bind(this));
diff --git a/packages/jest-worker/src/workers/NodeThreadsWorker.js b/packages/jest-worker/src/workers/NodeThreadsWorker.js
index fc0585e5d1bb..3b93ab822b7d 100644
--- a/packages/jest-worker/src/workers/NodeThreadsWorker.js
+++ b/packages/jest-worker/src/workers/NodeThreadsWorker.js
@@ -46,19 +46,14 @@ export default class ExperimentalWorker implements WorkerInterface {
       eval: false,
       stderr: true,
       stdout: true,
-      // $FlowFixMe: Flow does not work well with Object.assign.
-      workerData: Object.assign(
-        {
-          cwd: process.cwd(),
-          env: Object.assign({}, process.env, {
-            JEST_WORKER_ID: this._options.workerId,
-          }),
-          // Suppress --debug / --inspect flags while preserving others (like --harmony).
-          execArgv: process.execArgv.filter(v => !/^--(debug|inspect)/.test(v)),
-          silent: true,
-        },
-        this._options.forkOptions,
-      ),
+      workerData: {
+        cwd: process.cwd(),
+        env: {...process.env, JEST_WORKER_ID: this._options.workerId},
+        // Suppress --debug / --inspect flags while preserving others (like --harmony).
+        execArgv: process.execArgv.filter(v => !/^--(debug|inspect)/.test(v)),
+        silent: true,
+        ...this._options.forkOptions,
+      },
     });
 
     this._worker.on('message', this.onMessage.bind(this));
diff --git a/packages/jest-worker/src/workers/__tests__/ChildProcessWorker.test.js b/packages/jest-worker/src/workers/__tests__/ChildProcessWorker.test.js
index ccabd691559c..d6c5fc8790b7 100644
--- a/packages/jest-worker/src/workers/__tests__/ChildProcessWorker.test.js
+++ b/packages/jest-worker/src/workers/__tests__/ChildProcessWorker.test.js
@@ -65,9 +65,7 @@ it('passes fork options down to child_process.fork, adding the defaults', () =>
   expect(childProcess.fork.mock.calls[0][0]).toBe(child);
   expect(childProcess.fork.mock.calls[0][1]).toEqual({
     cwd: '/tmp', // Overridden default option.
-    env: Object.assign({}, process.env, {
-      FORCE_COLOR: supportsColor.stdout ? '1' : undefined,
-    }), // Default option.
+    env: {...process.env, FORCE_COLOR: supportsColor.stdout ? '1' : undefined}, // Default option.
     execArgv: ['-p'], // Filtered option.
     execPath: 'hello', // Added option.
     silent: true, // Default option.
diff --git a/packages/jest-worker/src/workers/processChild.js b/packages/jest-worker/src/workers/processChild.js
index a6b5f2077bc5..9becbba0fb49 100644
--- a/packages/jest-worker/src/workers/processChild.js
+++ b/packages/jest-worker/src/workers/processChild.js
@@ -96,7 +96,7 @@ function reportError(error: Error, type: PARENT_MESSAGE_ERROR) {
     error.message,
     error.stack,
     // $FlowFixMe: this is safe to just inherit from Object.
-    typeof error === 'object' ? Object.assign({}, error) : error,
+    typeof error === 'object' ? {...error} : error,
   ]);
 }
 
diff --git a/packages/jest-worker/src/workers/threadChild.js b/packages/jest-worker/src/workers/threadChild.js
index 17d087ee1ae9..e35e4610acc5 100644
--- a/packages/jest-worker/src/workers/threadChild.js
+++ b/packages/jest-worker/src/workers/threadChild.js
@@ -101,7 +101,7 @@ function reportError(error: Error, type: PARENT_MESSAGE_ERROR) {
     error.message,
     error.stack,
     // $FlowFixMe: this is safe to just inherit from Object.
-    typeof error === 'object' ? Object.assign({}, error) : error,
+    typeof error === 'object' ? {...error} : error,
   ]);
 }
 
diff --git a/packages/pretty-format/src/__tests__/getPrettyPrint.js b/packages/pretty-format/src/__tests__/getPrettyPrint.js
index b5dd8e4b2dde..3eae13b07dbc 100644
--- a/packages/pretty-format/src/__tests__/getPrettyPrint.js
+++ b/packages/pretty-format/src/__tests__/getPrettyPrint.js
@@ -16,15 +16,7 @@ const prettyFormat = require('../');
 
 const getPrettyPrint = (plugins: Plugins) =>
   function(received: any, expected: any, options?: OptionsReceived) {
-    const prettyFormatted = prettyFormat(
-      received,
-      Object.assign(
-        ({
-          plugins,
-        }: OptionsReceived),
-        options,
-      ),
-    );
+    const prettyFormatted = prettyFormat(received, {plugins, ...options});
     const pass = prettyFormatted === expected;
 
     const message = pass
diff --git a/packages/pretty-format/src/__tests__/react.test.js b/packages/pretty-format/src/__tests__/react.test.js
index 83694a19689a..6a268319cf99 100644
--- a/packages/pretty-format/src/__tests__/react.test.js
+++ b/packages/pretty-format/src/__tests__/react.test.js
@@ -20,26 +20,13 @@ const prettyFormat = require('..');
 const {ReactElement, ReactTestComponent} = prettyFormat.plugins;
 
 const formatElement = (element: any, options?: OptionsReceived) =>
-  prettyFormat(
-    element,
-    Object.assign(
-      ({
-        plugins: [ReactElement],
-      }: OptionsReceived),
-      options,
-    ),
-  );
+  prettyFormat(element, {plugins: [ReactElement], ...options});
 
 const formatTestObject = (object: any, options?: OptionsReceived) =>
-  prettyFormat(
-    object,
-    Object.assign(
-      ({
-        plugins: [ReactTestComponent, ReactElement],
-      }: OptionsReceived),
-      options,
-    ),
-  );
+  prettyFormat(object, {
+    plugins: [ReactTestComponent, ReactElement],
+    ...options,
+  });
 
 function assertPrintedJSX(
   val: any,
diff --git a/packages/pretty-format/src/plugins/DOMCollection.js b/packages/pretty-format/src/plugins/DOMCollection.js
index 86c71e23af3a..b45975022286 100644
--- a/packages/pretty-format/src/plugins/DOMCollection.js
+++ b/packages/pretty-format/src/plugins/DOMCollection.js
@@ -51,7 +51,7 @@ export const serialize = (
         printObjectProperties(
           name === 'NamedNodeMap'
             ? Array.prototype.reduce.call(collection, propsReducer, {})
-            : Object.assign({}, collection),
+            : {...collection},
           config,
           indentation,
           depth,