diff --git a/CHANGELOG.md b/CHANGELOG.md
index a760de897316..4e77fabe32bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -31,6 +31,7 @@
 - `[jest-haste-map]`: Migrate to TypeScript ([#7854](https://github.com/facebook/jest/pull/7854))
 - `[docs]`: Fix image paths in SnapshotTesting.md for current and version 24 ([#7872](https://github.com/facebook/jest/pull/7872))
 - `[babel-jest]`: Migrate to TypeScript ([#7862](https://github.com/facebook/jest/pull/7862))
+- `[jest-resolve]`: Migrate to TypeScript ([#7871](https://github.com/facebook/jest/pull/7871))
 
 ### Performance
 
diff --git a/e2e/__tests__/__snapshots__/moduleNameMapper.test.js.snap b/e2e/__tests__/__snapshots__/moduleNameMapper.test.js.snap
index 312abe793d4a..687ca938186f 100644
--- a/e2e/__tests__/__snapshots__/moduleNameMapper.test.js.snap
+++ b/e2e/__tests__/__snapshots__/moduleNameMapper.test.js.snap
@@ -30,6 +30,6 @@ FAIL __tests__/index.js
       12 | module.exports = () => 'test';
       13 | 
 
-      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:436:17)
+      at createNoMappedModuleFoundError (../../packages/jest-resolve/build/index.js:434:17)
       at Object.require (index.js:10:1)
 `;
diff --git a/e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.js.snap b/e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.js.snap
index 407b4c3bac23..13dc33fad1c2 100644
--- a/e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.js.snap
+++ b/e2e/__tests__/__snapshots__/resolveNoFileExtensions.test.js.snap
@@ -33,6 +33,6 @@ FAIL __tests__/test.js
         |                  ^
       4 | 
 
-      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:203:17)
+      at Resolver.resolveModule (../../packages/jest-resolve/build/index.js:201:17)
       at Object.require (index.js:3:18)
 `;
diff --git a/package.json b/package.json
index 08349c89df70..9767523ea0a2 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
     "progress": "^2.0.0",
     "promise": "^8.0.2",
     "readable-stream": "^3.0.3",
-    "realpath-native": "^1.0.0",
+    "realpath-native": "^1.1.0",
     "resolve": "^1.4.0",
     "rimraf": "^2.6.2",
     "slash": "^2.0.0",
diff --git a/packages/jest-cli/package.json b/packages/jest-cli/package.json
index 90c8e788397b..bc0caf236cad 100644
--- a/packages/jest-cli/package.json
+++ b/packages/jest-cli/package.json
@@ -35,7 +35,7 @@
     "p-each-series": "^1.0.0",
     "pirates": "^4.0.0",
     "prompts": "^2.0.1",
-    "realpath-native": "^1.0.0",
+    "realpath-native": "^1.1.0",
     "rimraf": "^2.5.4",
     "slash": "^2.0.0",
     "string-length": "^2.0.0",
diff --git a/packages/jest-config/package.json b/packages/jest-config/package.json
index c1dc8cde0f46..fb97cfa3117a 100644
--- a/packages/jest-config/package.json
+++ b/packages/jest-config/package.json
@@ -23,7 +23,7 @@
     "jest-validate": "^24.0.0",
     "micromatch": "^3.1.10",
     "pretty-format": "^24.0.0",
-    "realpath-native": "^1.0.2"
+    "realpath-native": "^1.1.0"
   },
   "devDependencies":  {
     "@types/babel__core": "^7.0.4",
diff --git a/packages/jest-haste-map/src/ModuleMap.ts b/packages/jest-haste-map/src/ModuleMap.ts
index 07246b1babcb..8b86aa2845e5 100644
--- a/packages/jest-haste-map/src/ModuleMap.ts
+++ b/packages/jest-haste-map/src/ModuleMap.ts
@@ -41,9 +41,9 @@ export default class ModuleMap {
 
   getModule(
     name: string,
-    platform: string | null,
-    supportsNativePlatform: boolean | null,
-    type: HTypeValue | null,
+    platform?: string | null,
+    supportsNativePlatform?: boolean | null,
+    type?: HTypeValue | null,
   ): Config.Path | null {
     if (type == null) {
       type = H.MODULE;
@@ -62,7 +62,7 @@ export default class ModuleMap {
 
   getPackage(
     name: string,
-    platform: string | null,
+    platform: string | null | undefined,
     _supportsNativePlatform: boolean | null,
   ): Config.Path | null {
     return this.getModule(name, platform, null, H.PACKAGE);
@@ -111,7 +111,7 @@ export default class ModuleMap {
    */
   private _getModuleMetadata(
     name: string,
-    platform: string | null,
+    platform: string | null | undefined,
     supportsNativePlatform: boolean,
   ): ModuleMetaData | null {
     const map = this._raw.map.get(name) || EMPTY_OBJ;
diff --git a/packages/jest-resolve/package.json b/packages/jest-resolve/package.json
index d44ad9c6b183..07bcc5de9bb7 100644
--- a/packages/jest-resolve/package.json
+++ b/packages/jest-resolve/package.json
@@ -8,15 +8,20 @@
   },
   "license": "MIT",
   "main": "build/index.js",
+  "types": "build/index.d.ts",
   "dependencies": {
+    "@jest/types": "^24.1.0",
     "browser-resolve": "^1.11.3",
     "chalk": "^2.0.1",
-    "realpath-native": "^1.0.0"
+    "realpath-native": "^1.1.0"
   },
   "devDependencies": {
     "@types/browser-resolve": "^0.0.5",
     "jest-haste-map": "^24.0.0"
   },
+  "peerDependencies": {
+    "jest-haste-map": "^24.0.0"
+  },
   "engines": {
     "node": ">= 6"
   },
diff --git a/packages/jest-resolve/src/__tests__/isBuiltinModule.test.js b/packages/jest-resolve/src/__tests__/isBuiltinModule.test.ts
similarity index 98%
rename from packages/jest-resolve/src/__tests__/isBuiltinModule.test.js
rename to packages/jest-resolve/src/__tests__/isBuiltinModule.test.ts
index ba68e4fa1b9e..0bbbb84d732b 100644
--- a/packages/jest-resolve/src/__tests__/isBuiltinModule.test.js
+++ b/packages/jest-resolve/src/__tests__/isBuiltinModule.test.ts
@@ -1,5 +1,4 @@
 // Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
-// @flow
 
 import isBuiltinModule from '../isBuiltinModule';
 
diff --git a/packages/jest-resolve/src/__tests__/resolve.test.js b/packages/jest-resolve/src/__tests__/resolve.test.ts
similarity index 92%
rename from packages/jest-resolve/src/__tests__/resolve.test.js
rename to packages/jest-resolve/src/__tests__/resolve.test.ts
index d074456ca2ad..014407bc47c7 100644
--- a/packages/jest-resolve/src/__tests__/resolve.test.js
+++ b/packages/jest-resolve/src/__tests__/resolve.test.ts
@@ -6,16 +6,18 @@
  *
  */
 
-'use strict';
-
 import fs from 'fs';
 import path from 'path';
-import {ModuleMap} from 'jest-haste-map';
-// eslint-disable-next-line import/default
+import HasteMap from 'jest-haste-map';
 import Resolver from '../';
+// @ts-ignore: js file
 import userResolver from '../__mocks__/userResolver';
 import nodeModulesPaths from '../nodeModulesPaths';
 import defaultResolver from '../defaultResolver';
+import {ResolverConfig} from '../types';
+
+// @ts-ignore: types are wrong. not sure how...
+const {ModuleMap} = HasteMap;
 
 jest.mock('../__mocks__/userResolver');
 
@@ -28,21 +30,21 @@ describe('isCoreModule', () => {
     const moduleMap = ModuleMap.create('/');
     const resolver = new Resolver(moduleMap, {
       hasCoreModules: false,
-    });
+    } as ResolverConfig);
     const isCore = resolver.isCoreModule('assert');
     expect(isCore).toEqual(false);
   });
 
   it('returns true if `hasCoreModules` is true and `moduleName` is a core module.', () => {
     const moduleMap = ModuleMap.create('/');
-    const resolver = new Resolver(moduleMap, {});
+    const resolver = new Resolver(moduleMap, {} as ResolverConfig);
     const isCore = resolver.isCoreModule('assert');
     expect(isCore).toEqual(true);
   });
 
   it('returns false if `hasCoreModules` is true and `moduleName` is not a core module.', () => {
     const moduleMap = ModuleMap.create('/');
-    const resolver = new Resolver(moduleMap, {});
+    const resolver = new Resolver(moduleMap, {} as ResolverConfig);
     const isCore = resolver.isCoreModule('not-a-core-module');
     expect(isCore).toEqual(false);
   });
@@ -84,7 +86,7 @@ describe('findNodeModule', () => {
 });
 
 describe('resolveModule', () => {
-  let moduleMap;
+  let moduleMap: typeof ModuleMap;
   beforeEach(() => {
     moduleMap = ModuleMap.create('/');
   });
@@ -92,7 +94,7 @@ describe('resolveModule', () => {
   it('is possible to resolve node modules', () => {
     const resolver = new Resolver(moduleMap, {
       extensions: ['.js'],
-    });
+    } as ResolverConfig);
     const src = require.resolve('../');
     const resolved = resolver.resolveModule(
       src,
@@ -104,7 +106,7 @@ describe('resolveModule', () => {
   it('is possible to resolve node modules with custom extensions', () => {
     const resolver = new Resolver(moduleMap, {
       extensions: ['.js', '.jsx'],
-    });
+    } as ResolverConfig);
     const src = require.resolve('../');
     const resolvedJsx = resolver.resolveModule(
       src,
@@ -119,7 +121,7 @@ describe('resolveModule', () => {
     const resolver = new Resolver(moduleMap, {
       extensions: ['.js', '.jsx'],
       platforms: ['native'],
-    });
+    } as ResolverConfig);
     const src = require.resolve('../');
     const resolvedJsx = resolver.resolveModule(
       src,
@@ -133,7 +135,7 @@ describe('resolveModule', () => {
   it('is possible to resolve node modules by resolving their realpath', () => {
     const resolver = new Resolver(moduleMap, {
       extensions: ['.js'],
-    });
+    } as ResolverConfig);
     const src = path.join(
       path.resolve(__dirname, '../../src/__mocks__/bar/node_modules/'),
       'foo/index.js',
@@ -147,7 +149,7 @@ describe('resolveModule', () => {
   it('is possible to specify custom resolve paths', () => {
     const resolver = new Resolver(moduleMap, {
       extensions: ['.js'],
-    });
+    } as ResolverConfig);
     const src = require.resolve('../');
     const resolved = resolver.resolveModule(src, 'mockJsDependency', {
       paths: [
@@ -173,7 +175,7 @@ describe('getMockModule', () => {
         },
       ],
       resolver: require.resolve('../__mocks__/userResolver'),
-    });
+    } as ResolverConfig);
     const src = require.resolve('../');
     resolver.getMockModule(src, 'dependentModule');
 
@@ -196,7 +198,7 @@ describe('nodeModulesPaths', () => {
 
 describe('Resolver.getModulePaths() -> nodeModulesPaths()', () => {
   const _path = path;
-  let moduleMap;
+  let moduleMap: typeof ModuleMap;
 
   beforeEach(() => {
     jest.resetModules();
@@ -208,7 +210,7 @@ describe('Resolver.getModulePaths() -> nodeModulesPaths()', () => {
     // This test suite won't work otherwise, since we cannot make assumptions
     // about the test environment when it comes to absolute paths.
     jest.doMock('realpath-native', () => ({
-      sync: dirInput => dirInput,
+      sync: (dirInput: string) => dirInput,
     }));
   });
 
diff --git a/packages/jest-resolve/src/defaultResolver.js b/packages/jest-resolve/src/defaultResolver.ts
similarity index 80%
rename from packages/jest-resolve/src/defaultResolver.js
rename to packages/jest-resolve/src/defaultResolver.ts
index 3549bf4d1933..6cda0840d98e 100644
--- a/packages/jest-resolve/src/defaultResolver.js
+++ b/packages/jest-resolve/src/defaultResolver.ts
@@ -3,33 +3,29 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-import type {Path} from 'types/Config';
-import type {ErrorWithCode} from 'types/Errors';
-
-import browserResolve from 'browser-resolve';
 import fs from 'fs';
 import path from 'path';
+import browserResolve from 'browser-resolve';
+import {Config} from '@jest/types';
 import isBuiltinModule from './isBuiltinModule';
 import nodeModulesPaths from './nodeModulesPaths';
 
-type ResolverOptions = {|
-  basedir: Path,
-  browser?: boolean,
-  defaultResolver: typeof defaultResolver,
-  extensions?: Array<string>,
-  moduleDirectory?: Array<string>,
-  paths?: ?Array<Path>,
-  rootDir: ?Path,
-|};
+type ResolverOptions = {
+  basedir: Config.Path;
+  browser?: boolean;
+  defaultResolver: typeof defaultResolver;
+  extensions?: Array<string>;
+  moduleDirectory?: Array<string>;
+  paths?: Array<Config.Path>;
+  rootDir?: Config.Path;
+};
 
 export default function defaultResolver(
-  path: Path,
+  path: Config.Path,
   options: ResolverOptions,
-): Path {
+): Config.Path {
   const resolve = options.browser ? browserResolve.sync : resolveSync;
 
   return resolve(path, {
@@ -44,7 +40,10 @@ export default function defaultResolver(
 
 const REGEX_RELATIVE_IMPORT = /^(?:\.\.?(?:\/|$)|\/|([A-Za-z]:)?[\\\/])/;
 
-function resolveSync(target: Path, options: ResolverOptions): Path {
+function resolveSync(
+  target: Config.Path,
+  options: ResolverOptions,
+): Config.Path {
   const basedir = options.basedir;
   const extensions = options.extensions || ['.js'];
   const paths = options.paths || [];
@@ -75,7 +74,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
     return target;
   }
 
-  const err: ErrorWithCode = new Error(
+  const err: Error & {code?: string} = new Error(
     "Cannot find module '" + target + "' from '" + basedir + "'",
   );
   err.code = 'MODULE_NOT_FOUND';
@@ -84,7 +83,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
   /*
    * contextual helper functions
    */
-  function tryResolve(name: Path): ?Path {
+  function tryResolve(name: Config.Path): Config.Path | undefined {
     const dir = path.dirname(name);
     let result;
     if (isDirectory(dir)) {
@@ -98,7 +97,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
     return result;
   }
 
-  function resolveAsFile(name: Path): ?Path {
+  function resolveAsFile(name: Config.Path): Config.Path | undefined {
     if (isFile(name)) {
       return name;
     }
@@ -113,7 +112,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
     return undefined;
   }
 
-  function resolveAsDirectory(name: Path): ?Path {
+  function resolveAsDirectory(name: Config.Path): Config.Path | undefined {
     if (!isDirectory(name)) {
       return undefined;
     }
@@ -140,7 +139,7 @@ function resolveSync(target: Path, options: ResolverOptions): Path {
 /*
  * helper functions
  */
-function isFile(file: Path): boolean {
+function isFile(file: Config.Path): boolean {
   let result;
 
   try {
@@ -156,7 +155,7 @@ function isFile(file: Path): boolean {
   return result;
 }
 
-function isDirectory(dir: Path): boolean {
+function isDirectory(dir: Config.Path): boolean {
   let result;
 
   try {
@@ -172,6 +171,6 @@ function isDirectory(dir: Path): boolean {
   return result;
 }
 
-function isCurrentDirectory(testPath: Path): boolean {
+function isCurrentDirectory(testPath: Config.Path): boolean {
   return path.resolve('.') === path.resolve(testPath);
 }
diff --git a/packages/jest-resolve/src/index.js b/packages/jest-resolve/src/index.ts
similarity index 83%
rename from packages/jest-resolve/src/index.js
rename to packages/jest-resolve/src/index.ts
index b75fb2b6afd0..cfc053f08001 100644
--- a/packages/jest-resolve/src/index.js
+++ b/packages/jest-resolve/src/index.ts
@@ -3,51 +3,34 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-import type {Path} from 'types/Config';
-import type {ModuleMap} from 'types/HasteMap';
-import type {ResolveModuleConfig} from 'types/Resolve';
-import type {ErrorWithCode} from 'types/Errors';
-
 import path from 'path';
+import {Config} from '@jest/types';
+import {ModuleMap} from 'jest-haste-map';
 import {sync as realpath} from 'realpath-native';
+import chalk from 'chalk';
 import nodeModulesPaths from './nodeModulesPaths';
 import isBuiltinModule from './isBuiltinModule';
 import defaultResolver from './defaultResolver';
-import chalk from 'chalk';
+import {ResolverConfig} from './types';
 
-type ResolverConfig = {|
-  browser?: boolean,
-  defaultPlatform: ?string,
-  extensions: Array<string>,
-  hasCoreModules: boolean,
-  moduleDirectories: Array<string>,
-  moduleNameMapper: ?Array<ModuleNameMapperConfig>,
-  modulePaths: Array<Path>,
-  platforms?: Array<string>,
-  resolver: ?Path,
-  rootDir: ?Path,
-|};
-
-type FindNodeModuleConfig = {|
-  basedir: Path,
-  browser?: boolean,
-  extensions?: Array<string>,
-  moduleDirectory?: Array<string>,
-  paths?: Array<Path>,
-  resolver?: ?Path,
-  rootDir?: ?Path,
-|};
-
-type ModuleNameMapperConfig = {|
-  regex: RegExp,
-  moduleName: string,
-|};
+type ResolveModuleConfig = {
+  skipNodeResolution?: boolean;
+  paths?: Config.Path[];
+};
 
-type BooleanObject = {[key: string]: boolean, __proto__: null};
+type FindNodeModuleConfig = {
+  basedir: Config.Path;
+  browser?: boolean;
+  extensions?: Array<string>;
+  moduleDirectory?: Array<string>;
+  paths?: Array<Config.Path>;
+  resolver?: Config.Path;
+  rootDir?: Config.Path;
+};
+
+type BooleanObject = {[key: string]: boolean};
 
 const NATIVE_PLATFORM = 'native';
 
@@ -62,12 +45,12 @@ const nodePaths = process.env.NODE_PATH
   : null;
 
 class Resolver {
-  _options: ResolverConfig;
-  _moduleMap: ModuleMap;
-  _moduleIDCache: {[key: string]: string, __proto__: null};
-  _moduleNameCache: {[name: string]: Path, __proto__: null};
-  _modulePathCache: {[path: Path]: Array<Path>, __proto__: null};
-  _supportsNativePlatform: boolean;
+  private readonly _options: ResolverConfig;
+  private readonly _moduleMap: ModuleMap;
+  private readonly _moduleIDCache: {[key: string]: string};
+  private readonly _moduleNameCache: {[name: string]: Config.Path};
+  private readonly _modulePathCache: {[path: string]: Array<Config.Path>};
+  private readonly _supportsNativePlatform: boolean;
 
   constructor(moduleMap: ModuleMap, options: ResolverConfig) {
     this._options = {
@@ -92,7 +75,10 @@ class Resolver {
     this._modulePathCache = Object.create(null);
   }
 
-  static findNodeModule(path: Path, options: FindNodeModuleConfig): ?Path {
+  static findNodeModule(
+    path: Config.Path,
+    options: FindNodeModuleConfig,
+  ): Config.Path | null {
     const resolver = options.resolver
       ? /* $FlowFixMe */
         require(options.resolver)
@@ -114,10 +100,10 @@ class Resolver {
   }
 
   resolveModuleFromDirIfExists(
-    dirname: Path,
+    dirname: Config.Path,
     moduleName: string,
     options?: ResolveModuleConfig,
-  ): ?Path {
+  ): Config.Path | null {
     const paths = (options && options.paths) || this._options.modulePaths;
     const moduleDirectory = this._options.moduleDirectories;
     const key = dirname + path.delimiter + moduleName;
@@ -157,7 +143,7 @@ class Resolver {
     const skipResolution =
       options && options.skipNodeResolution && !moduleName.includes(path.sep);
 
-    const resolveNodeModule = name =>
+    const resolveNodeModule = (name: Config.Path) =>
       Resolver.findNodeModule(name, {
         basedir: dirname,
         browser: this._options.browser,
@@ -179,7 +165,7 @@ class Resolver {
     // 4. Resolve "haste packages" which are `package.json` files outside of
     // `node_modules` folders anywhere in the file system.
     const parts = moduleName.split('/');
-    const hastePackage = this.getPackage(parts.shift());
+    const hastePackage = this.getPackage(parts.shift()!);
     if (hastePackage) {
       try {
         const module = path.join.apply(
@@ -197,10 +183,10 @@ class Resolver {
   }
 
   resolveModule(
-    from: Path,
+    from: Config.Path,
     moduleName: string,
     options?: ResolveModuleConfig,
-  ): Path {
+  ): Config.Path {
     const dirname = path.dirname(from);
     const module = this.resolveModuleFromDirIfExists(
       dirname,
@@ -213,10 +199,10 @@ class Resolver {
     // produces an error based on the dirname but we have the actual current
     // module name available.
     const relativePath = path.relative(dirname, from);
-    const err = new Error(
+    const err: Error & {code?: string} = new Error(
       `Cannot find module '${moduleName}' from '${relativePath || '.'}'`,
     );
-    (err: ErrorWithCode).code = 'MODULE_NOT_FOUND';
+    err.code = 'MODULE_NOT_FOUND';
     throw err;
   }
 
@@ -224,7 +210,7 @@ class Resolver {
     return this._options.hasCoreModules && isBuiltinModule(moduleName);
   }
 
-  getModule(name: string): ?Path {
+  getModule(name: string): Config.Path | null {
     return this._moduleMap.getModule(
       name,
       this._options.defaultPlatform,
@@ -232,14 +218,14 @@ class Resolver {
     );
   }
 
-  getModulePath(from: Path, moduleName: string) {
+  getModulePath(from: Config.Path, moduleName: string) {
     if (moduleName[0] !== '.' || path.isAbsolute(moduleName)) {
       return moduleName;
     }
     return path.normalize(path.dirname(from) + '/' + moduleName);
   }
 
-  getPackage(name: string): ?Path {
+  getPackage(name: string): Config.Path | null {
     return this._moduleMap.getPackage(
       name,
       this._options.defaultPlatform,
@@ -247,7 +233,7 @@ class Resolver {
     );
   }
 
-  getMockModule(from: Path, name: string): ?Path {
+  getMockModule(from: Config.Path, name: string): Config.Path | null {
     const mock = this._moduleMap.getMockModule(name);
     if (mock) {
       return mock;
@@ -260,7 +246,7 @@ class Resolver {
     return null;
   }
 
-  getModulePaths(from: Path): Array<Path> {
+  getModulePaths(from: Config.Path): Array<Config.Path> {
     if (!this._modulePathCache[from]) {
       const moduleDirectory = this._options.moduleDirectories;
       const paths = nodeModulesPaths(from, {moduleDirectory});
@@ -275,8 +261,8 @@ class Resolver {
 
   getModuleID(
     virtualMocks: BooleanObject,
-    from: Path,
-    _moduleName?: ?string,
+    from: Config.Path,
+    _moduleName?: string,
   ): string {
     const moduleName = _moduleName || '';
 
@@ -299,15 +285,15 @@ class Resolver {
     return (this._moduleIDCache[key] = id);
   }
 
-  _getModuleType(moduleName: string): 'node' | 'user' {
+  private _getModuleType(moduleName: string): 'node' | 'user' {
     return this.isCoreModule(moduleName) ? 'node' : 'user';
   }
 
-  _getAbsolutePath(
+  private _getAbsolutePath(
     virtualMocks: BooleanObject,
-    from: Path,
+    from: Config.Path,
     moduleName: string,
-  ): ?string {
+  ): Config.Path | null {
     if (this.isCoreModule(moduleName)) {
       return moduleName;
     }
@@ -316,17 +302,20 @@ class Resolver {
       : this._getVirtualMockPath(virtualMocks, from, moduleName);
   }
 
-  _getMockPath(from: Path, moduleName: string): ?string {
+  private _getMockPath(
+    from: Config.Path,
+    moduleName: string,
+  ): Config.Path | null {
     return !this.isCoreModule(moduleName)
       ? this.getMockModule(from, moduleName)
       : null;
   }
 
-  _getVirtualMockPath(
+  private _getVirtualMockPath(
     virtualMocks: BooleanObject,
-    from: Path,
+    from: Config.Path,
     moduleName: string,
-  ): Path {
+  ): Config.Path {
     const virtualMockPath = this.getModulePath(from, moduleName);
     return virtualMocks[virtualMockPath]
       ? virtualMockPath
@@ -335,13 +324,16 @@ class Resolver {
       : from;
   }
 
-  _isModuleResolved(from: Path, moduleName: string): boolean {
+  private _isModuleResolved(from: Config.Path, moduleName: string): boolean {
     return !!(
       this.getModule(moduleName) || this.getMockModule(from, moduleName)
     );
   }
 
-  resolveStubModuleName(from: Path, moduleName: string): ?Path {
+  resolveStubModuleName(
+    from: Config.Path,
+    moduleName: string,
+  ): Config.Path | null {
     const dirname = path.dirname(from);
     const paths = this._options.modulePaths;
     const extensions = this._options.extensions.slice();
@@ -404,11 +396,11 @@ class Resolver {
 }
 
 const createNoMappedModuleFoundError = (
-  moduleName,
-  updatedName,
-  mappedModuleName,
-  regex,
-  resolver,
+  moduleName: string,
+  updatedName: string,
+  mappedModuleName: string,
+  regex: RegExp,
+  resolver: Function | string,
 ) => {
   const error = new Error(
     chalk.red(`${chalk.bold('Configuration error')}:
@@ -430,4 +422,4 @@ Please check your configuration for these entries:
   return error;
 };
 
-module.exports = Resolver;
+export = Resolver;
diff --git a/packages/jest-resolve/src/isBuiltinModule.js b/packages/jest-resolve/src/isBuiltinModule.ts
similarity index 67%
rename from packages/jest-resolve/src/isBuiltinModule.js
rename to packages/jest-resolve/src/isBuiltinModule.ts
index bd674f65864e..c7e64c914434 100644
--- a/packages/jest-resolve/src/isBuiltinModule.js
+++ b/packages/jest-resolve/src/isBuiltinModule.ts
@@ -3,23 +3,20 @@
  *
  * This source code is licensed under the MIT license found in the
  * LICENSE file in the root directory of this source tree.
- *
- * @flow
  */
 
-// $FlowFixMe: Flow doesn't know about the `module` module
-import {builtinModules} from 'module';
+import module from 'module';
 
-// https://github.com/facebook/flow/pull/5160
-declare var process: {
-  binding(type: string): {},
+// @ts-ignore: "private" api
+declare const process: {
+  binding(type: string): {};
 };
 
 const EXPERIMENTAL_MODULES = ['worker_threads'];
 
 const BUILTIN_MODULES = new Set(
-  builtinModules
-    ? builtinModules.concat(EXPERIMENTAL_MODULES)
+  module.builtinModules
+    ? module.builtinModules.concat(EXPERIMENTAL_MODULES)
     : Object.keys(process.binding('natives'))
         .filter((module: string) => !/^internal\//.test(module))
         .concat(EXPERIMENTAL_MODULES),
diff --git a/packages/jest-resolve/src/nodeModulesPaths.js b/packages/jest-resolve/src/nodeModulesPaths.ts
similarity index 84%
rename from packages/jest-resolve/src/nodeModulesPaths.js
rename to packages/jest-resolve/src/nodeModulesPaths.ts
index 3e714f9d2b3d..4526660808d6 100644
--- a/packages/jest-resolve/src/nodeModulesPaths.js
+++ b/packages/jest-resolve/src/nodeModulesPaths.ts
@@ -5,26 +5,24 @@
  * LICENSE file in the root directory of this source tree.
  *
  * Adapted from: https://github.com/substack/node-resolve
- *
- * @flow
  */
 
-import type {Path} from 'types/Config';
 import path from 'path';
+import {Config} from '@jest/types';
 import {sync as realpath} from 'realpath-native';
 
-type NodeModulesPathsOptions = {|
-  moduleDirectory?: Array<string>,
-  paths?: ?Array<Path>,
-|};
+type NodeModulesPathsOptions = {
+  moduleDirectory?: Array<string>;
+  paths?: Array<Config.Path>;
+};
 
 export default function nodeModulesPaths(
-  basedir: Path,
+  basedir: Config.Path,
   options: NodeModulesPathsOptions,
-): Path[] {
+): Config.Path[] {
   const modules =
     options && options.moduleDirectory
-      ? [].concat(options.moduleDirectory)
+      ? Array.from(options.moduleDirectory)
       : ['node_modules'];
 
   // ensure that `basedir` is an absolute path at this point,
@@ -48,7 +46,7 @@ export default function nodeModulesPaths(
     physicalBasedir = basedirAbs;
   }
 
-  const paths = [physicalBasedir];
+  const paths: Array<Config.Path> = [physicalBasedir];
   let parsed = path.parse(physicalBasedir);
   while (parsed.dir !== paths[paths.length - 1]) {
     paths.push(parsed.dir);
@@ -67,7 +65,7 @@ export default function nodeModulesPaths(
               : path.join(prefix, aPath, moduleDir),
           ),
         ),
-      [],
+      [] as Array<Config.Path>,
     )
     .filter(dir => dir !== '');
 
diff --git a/packages/jest-resolve/src/types.ts b/packages/jest-resolve/src/types.ts
new file mode 100644
index 000000000000..b765f0333107
--- /dev/null
+++ b/packages/jest-resolve/src/types.ts
@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+import {Config} from '@jest/types';
+
+export type ResolverConfig = {
+  browser?: boolean;
+  defaultPlatform?: string;
+  extensions: Array<string>;
+  hasCoreModules: boolean;
+  moduleDirectories: Array<string>;
+  moduleNameMapper?: Array<ModuleNameMapperConfig>;
+  modulePaths: Array<Config.Path>;
+  platforms?: Array<string>;
+  resolver: Config.Path;
+  rootDir: Config.Path;
+};
+
+type ModuleNameMapperConfig = {
+  regex: RegExp;
+  moduleName: string;
+};
diff --git a/packages/jest-resolve/tsconfig.json b/packages/jest-resolve/tsconfig.json
new file mode 100644
index 000000000000..befa0d307f51
--- /dev/null
+++ b/packages/jest-resolve/tsconfig.json
@@ -0,0 +1,8 @@
+{
+  "extends": "../../tsconfig.json",
+  "compilerOptions": {
+    "rootDir": "src",
+    "outDir": "build"
+  },
+  "references": [{"path":  "../jest-types"}, {"path":  "../jest-haste-map"}]
+}
diff --git a/packages/jest-runtime/package.json b/packages/jest-runtime/package.json
index 2bfa2989ad6d..8524b6900536 100644
--- a/packages/jest-runtime/package.json
+++ b/packages/jest-runtime/package.json
@@ -26,7 +26,7 @@
     "jest-util": "^24.0.0",
     "jest-validate": "^24.0.0",
     "micromatch": "^3.1.10",
-    "realpath-native": "^1.0.0",
+    "realpath-native": "^1.1.0",
     "slash": "^2.0.0",
     "strip-bom": "^3.0.0",
     "write-file-atomic": "2.4.1",
diff --git a/yarn.lock b/yarn.lock
index 4d6dea0f8c63..111752599f80 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -11063,10 +11063,10 @@ readdirp@^2.0.0:
     micromatch "^3.1.10"
     readable-stream "^2.0.2"
 
-realpath-native@^1.0.0, realpath-native@^1.0.2:
-  version "1.0.2"
-  resolved "https://registry.yarnpkg.com/realpath-native/-/realpath-native-1.0.2.tgz#cd51ce089b513b45cf9b1516c82989b51ccc6560"
-  integrity sha512-+S3zTvVt9yTntFrBpm7TQmQ3tzpCrnA1a/y+3cUHAc9ZR6aIjG0WNLR+Rj79QpJktY+VeW/TQtFlQ1bzsehI8g==
+realpath-native@^1.1.0:
+  version "1.1.0"
+  resolved "https://registry.yarnpkg.com/realpath-native/-/realpath-native-1.1.0.tgz#2003294fea23fb0672f2476ebe22fcf498a2d65c"
+  integrity sha512-wlgPA6cCIIg9gKz0fgAPjnzh4yR/LnXovwuo9hvyGvx3h8nX4+/iLZplfUWasXpqD8BdnGnP5njOFjkUwPzvjA==
   dependencies:
     util.promisify "^1.0.0"