diff --git a/packages/cli/src/commands/doctor/doctor.js b/packages/cli/src/commands/doctor/doctor.js
index 0592dcfa5..474bd6e43 100644
--- a/packages/cli/src/commands/doctor/doctor.js
+++ b/packages/cli/src/commands/doctor/doctor.js
@@ -1,14 +1,13 @@
 // @flow
 import chalk from 'chalk';
 import envinfo from 'envinfo';
-import Ora from 'ora';
 import {logger} from '@react-native-community/cli-tools';
 import {getHealthchecks, HEALTHCHECK_TYPES} from './healthchecks';
 import {getLoader} from '../../tools/loader';
 import printFixOptions, {KEYS} from './printFixOptions';
 import runAutomaticFix, {AUTOMATIC_FIX_LEVELS} from './runAutomaticFix';
 import type {ConfigT} from 'types';
-import type {EnvironmentInfo} from './types';
+import type {HealthCheckInterface} from './types';
 
 const printCategory = ({label, key}) => {
   if (key > 0) {
@@ -74,18 +73,7 @@ export default (async function runDoctor(
     healthchecks,
   }: {
     label: string,
-    healthchecks: Array<{
-      label: string,
-      visible: boolean,
-      isRequired: boolean,
-      getDiagnostics: (
-        envInfor: EnvironmentInfo,
-      ) => {version: string, needsToBeFixed: boolean},
-      getDiagnosticsAsync: (
-        envInfor: EnvironmentInfo,
-      ) => Promise<{version: string, needsToBeFixed: boolean}>,
-      runAutomaticFix: (args: {loader: typeof Ora}) => Promise<void>,
-    }>,
+    healthchecks: Array<HealthCheckInterface>,
   }) => ({
     label,
     healthchecks: (await Promise.all(
@@ -94,9 +82,9 @@ export default (async function runDoctor(
           return;
         }
 
-        const {needsToBeFixed} = healthcheck.getDiagnostics
-          ? healthcheck.getDiagnostics(environmentInfo)
-          : await healthcheck.getDiagnosticsAsync(environmentInfo);
+        const {needsToBeFixed} = await healthcheck.getDiagnostics(
+          environmentInfo,
+        );
 
         // Assume that it's required unless specified otherwise
         const isRequired = healthcheck.isRequired !== false;
@@ -104,7 +92,7 @@ export default (async function runDoctor(
 
         return {
           label: healthcheck.label,
-          needsToBeFixed,
+          needsToBeFixed: Boolean(needsToBeFixed),
           runAutomaticFix: healthcheck.runAutomaticFix,
           isRequired,
           type: needsToBeFixed
@@ -125,6 +113,7 @@ export default (async function runDoctor(
     );
 
   const iterateOverCategories = categories =>
+    // $FlowFixMe - bad Object.values typings
     Promise.all(categories.map(iterateOverHealthChecks));
 
   const healthchecksPerCategory = await iterateOverCategories(
@@ -167,6 +156,7 @@ export default (async function runDoctor(
   }
 
   const onKeyPress = async key => {
+    // $FlowFixMe
     process.stdin.setRawMode(false);
     process.stdin.removeAllListeners('data');
 
diff --git a/packages/cli/src/commands/doctor/healthchecks/androidHomeEnvVariable.js b/packages/cli/src/commands/doctor/healthchecks/androidHomeEnvVariable.js
index 7572448de..410b9855d 100644
--- a/packages/cli/src/commands/doctor/healthchecks/androidHomeEnvVariable.js
+++ b/packages/cli/src/commands/doctor/healthchecks/androidHomeEnvVariable.js
@@ -2,6 +2,7 @@
 import chalk from 'chalk';
 import Ora from 'ora';
 import {logManualInstallation} from './common';
+import type {HealthCheckInterface} from '../types';
 
 // List of answers on how to set `ANDROID_HOME` for each platform
 const URLS = {
@@ -12,9 +13,9 @@ const URLS = {
 
 const label = 'ANDROID_HOME';
 
-export default {
+export default ({
   label,
-  getDiagnostics: () => ({
+  getDiagnostics: async () => ({
     needsToBeFixed: !process.env.ANDROID_HOME,
   }),
   runAutomaticFix: async ({loader}: {loader: typeof Ora}) => {
@@ -26,4 +27,4 @@ export default {
       )}.`,
     });
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/androidNDK.js b/packages/cli/src/commands/doctor/healthchecks/androidNDK.js
index 848994597..d3481e1fe 100644
--- a/packages/cli/src/commands/doctor/healthchecks/androidNDK.js
+++ b/packages/cli/src/commands/doctor/healthchecks/androidNDK.js
@@ -4,11 +4,11 @@ import Ora from 'ora';
 import {logManualInstallation} from './common';
 import versionRanges from '../versionRanges';
 import {doesSoftwareNeedToBeFixed} from '../checkInstallation';
-import type {EnvironmentInfo} from '../types';
+import type {EnvironmentInfo, HealthCheckInterface} from '../types';
 
-export default {
+export default ({
   label: 'Android NDK',
-  getDiagnosticsAsync: async ({SDKs}: EnvironmentInfo) => ({
+  getDiagnostics: async ({SDKs}: EnvironmentInfo) => ({
     needsToBeFixed: doesSoftwareNeedToBeFixed({
       version: SDKs['Android SDK']['Android NDK'],
       versionRange: versionRanges.ANDROID_NDK,
@@ -39,4 +39,4 @@ export default {
       url: 'https://developer.android.com/ndk/downloads',
     });
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/androidSDK.js b/packages/cli/src/commands/doctor/healthchecks/androidSDK.js
index 1faa8d3cb..c82e0eaf5 100644
--- a/packages/cli/src/commands/doctor/healthchecks/androidSDK.js
+++ b/packages/cli/src/commands/doctor/healthchecks/androidSDK.js
@@ -5,14 +5,15 @@ import {logManualInstallation} from './common';
 import versionRanges from '../versionRanges';
 import {doesSoftwareNeedToBeFixed} from '../checkInstallation';
 import execa from 'execa';
+import type {EnvironmentInfo, HealthCheckInterface} from '../types';
 
 const installMessage = `Read more about how to update Android SDK at ${chalk.dim(
   'https://developer.android.com/studio',
 )}`;
 
-export default {
+export default ({
   label: 'Android SDK',
-  getDiagnosticsAsync: async ({SDKs}: EnvironmentInfo) => {
+  getDiagnostics: async ({SDKs}: EnvironmentInfo) => {
     let sdks = SDKs['Android SDK'];
 
     // This is a workaround for envinfo's Android SDK check not working on
@@ -20,6 +21,7 @@ export default {
     // See the PR: https://github.com/tabrindle/envinfo/pull/119
     if (sdks === 'Not Found' && process.platform !== 'darwin') {
       try {
+        // $FlowFixMe bad execa types
         const {stdout} = await execa(
           process.env.ANDROID_HOME
             ? `${process.env.ANDROID_HOME}/tools/bin/sdkmanager`
@@ -31,7 +33,9 @@ export default {
         const regex = /build-tools;([\d|.]+)[\S\s]/g;
         let match = null;
         while ((match = regex.exec(stdout)) !== null) {
-          matches.push(match[1]);
+          if (match) {
+            matches.push(match[1]);
+          }
         }
         if (matches.length > 0) {
           sdks = {
@@ -44,10 +48,11 @@ export default {
     return {
       needsToBeFixed:
         (sdks === 'Not Found' && installMessage) ||
-        doesSoftwareNeedToBeFixed({
-          version: sdks['Build Tools'][0],
-          versionRange: versionRanges.ANDROID_NDK,
-        }),
+        (sdks !== 'Not Found' &&
+          doesSoftwareNeedToBeFixed({
+            version: sdks['Build Tools'][0],
+            versionRange: versionRanges.ANDROID_NDK,
+          })),
     };
   },
   runAutomaticFix: async ({
@@ -73,4 +78,4 @@ export default {
       url: 'https://facebook.github.io/react-native/docs/getting-started',
     });
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/cocoaPods.js b/packages/cli/src/commands/doctor/healthchecks/cocoaPods.js
index dd8597b99..5644278c6 100644
--- a/packages/cli/src/commands/doctor/healthchecks/cocoaPods.js
+++ b/packages/cli/src/commands/doctor/healthchecks/cocoaPods.js
@@ -1,10 +1,12 @@
+// @flow
 import {isSoftwareInstalled} from '../checkInstallation';
 import {installCocoaPods} from '../../../tools/installPods';
+import {type HealthCheckInterface} from '../types';
 
-export default {
+export default ({
   label: 'CocoaPods',
-  getDiagnosticsAsync: async () => ({
+  getDiagnostics: async () => ({
     needsToBeFixed: !(await isSoftwareInstalled('pod')),
   }),
   runAutomaticFix: async ({loader}) => await installCocoaPods(loader),
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/iosDeploy.js b/packages/cli/src/commands/doctor/healthchecks/iosDeploy.js
index d4df9774b..7c104e240 100644
--- a/packages/cli/src/commands/doctor/healthchecks/iosDeploy.js
+++ b/packages/cli/src/commands/doctor/healthchecks/iosDeploy.js
@@ -4,6 +4,7 @@ import Ora from 'ora';
 import {isSoftwareInstalled, PACKAGE_MANAGERS} from '../checkInstallation';
 import {packageManager} from './packageManagers';
 import {logManualInstallation} from './common';
+import type {HealthCheckInterface} from '../types';
 
 const getInstallationCommand = () => {
   if (packageManager === PACKAGE_MANAGERS.YARN) {
@@ -17,10 +18,10 @@ const getInstallationCommand = () => {
   return undefined;
 };
 
-export default {
+export default ({
   label: 'ios-deploy',
   isRequired: false,
-  getDiagnosticsAsync: async () => ({
+  getDiagnostics: async () => ({
     needsToBeFixed: !(await isSoftwareInstalled('ios-deploy')),
   }),
   runAutomaticFix: async ({loader}: {loader: typeof Ora}) => {
@@ -53,4 +54,4 @@ export default {
       });
     }
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/nodeJS.js b/packages/cli/src/commands/doctor/healthchecks/nodeJS.js
index 562ed3d15..a4dfdd8eb 100644
--- a/packages/cli/src/commands/doctor/healthchecks/nodeJS.js
+++ b/packages/cli/src/commands/doctor/healthchecks/nodeJS.js
@@ -3,11 +3,11 @@ import Ora from 'ora';
 import versionRanges from '../versionRanges';
 import {doesSoftwareNeedToBeFixed} from '../checkInstallation';
 import {logManualInstallation} from './common';
-import type {EnvironmentInfo} from '../types';
+import type {EnvironmentInfo, HealthCheckInterface} from '../types';
 
-export default {
+export default ({
   label: 'Node.js',
-  getDiagnostics: ({Binaries}: EnvironmentInfo) => ({
+  getDiagnostics: async ({Binaries}: EnvironmentInfo) => ({
     version: Binaries.Node.version,
     needsToBeFixed: doesSoftwareNeedToBeFixed({
       version: Binaries.Node.version,
@@ -22,4 +22,4 @@ export default {
       url: 'https://nodejs.org/en/download/',
     });
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/healthchecks/packageManagers.js b/packages/cli/src/commands/doctor/healthchecks/packageManagers.js
index 5ed9a2b26..92433c7ad 100644
--- a/packages/cli/src/commands/doctor/healthchecks/packageManagers.js
+++ b/packages/cli/src/commands/doctor/healthchecks/packageManagers.js
@@ -1,12 +1,13 @@
 // @flow
 import fs from 'fs';
+import Ora from 'ora';
 import versionRanges from '../versionRanges';
 import {
   PACKAGE_MANAGERS,
   doesSoftwareNeedToBeFixed,
 } from '../checkInstallation';
 import {install} from '../../../tools/install';
-import type {EnvironmentInfo} from '../types';
+import type {EnvironmentInfo, HealthCheckInterface} from '../types';
 
 const packageManager = (() => {
   if (fs.existsSync('yarn.lock')) {
@@ -20,9 +21,9 @@ const packageManager = (() => {
   return undefined;
 })();
 
-const yarn = {
+const yarn: HealthCheckInterface = {
   label: 'yarn',
-  getDiagnostics: ({Binaries}: EnvironmentInfo) => ({
+  getDiagnostics: async ({Binaries}: EnvironmentInfo) => ({
     version: Binaries.Node.version,
     needsToBeFixed: doesSoftwareNeedToBeFixed({
       version: Binaries.Yarn.version,
@@ -33,13 +34,13 @@ const yarn = {
   // or if we can't identify that the user uses yarn or npm
   visible:
     packageManager === PACKAGE_MANAGERS.YARN || packageManager === undefined,
-  runAutomaticFix: async ({loader}) =>
+  runAutomaticFix: async ({loader}: typeof Ora) =>
     await install('yarn', 'https://yarnpkg.com/docs/install', loader),
 };
 
-const npm = {
+const npm: HealthCheckInterface = {
   label: 'npm',
-  getDiagnostics: ({Binaries}: EnvironmentInfo) => ({
+  getDiagnostics: async ({Binaries}: EnvironmentInfo) => ({
     needsToBeFixed: doesSoftwareNeedToBeFixed({
       version: Binaries.npm.version,
       versionRange: versionRanges.NPM,
@@ -49,7 +50,7 @@ const npm = {
   // or if we can't identify that the user uses yarn or npm
   visible:
     packageManager === PACKAGE_MANAGERS.NPM || packageManager === undefined,
-  runAutomaticFix: async ({loader}) =>
+  runAutomaticFix: async ({loader}: typeof Ora) =>
     await install('node', 'https://nodejs.org/', loader),
 };
 
diff --git a/packages/cli/src/commands/doctor/healthchecks/watchman.js b/packages/cli/src/commands/doctor/healthchecks/watchman.js
index d4857577b..798708a78 100644
--- a/packages/cli/src/commands/doctor/healthchecks/watchman.js
+++ b/packages/cli/src/commands/doctor/healthchecks/watchman.js
@@ -1,4 +1,5 @@
 // @flow
+import Ora from 'ora';
 import versionRanges from '../versionRanges';
 import {doesSoftwareNeedToBeFixed} from '../checkInstallation';
 import {install} from '../../../tools/install';
@@ -12,7 +13,7 @@ export default {
       versionRange: versionRanges.WATCHMAN,
     }),
   }),
-  runAutomaticFix: async ({loader}) =>
+  runAutomaticFix: async ({loader}: typeof Ora) =>
     await install(
       'watchman',
       'https://facebook.github.io/watchman/docs/install.html',
diff --git a/packages/cli/src/commands/doctor/healthchecks/xcode.js b/packages/cli/src/commands/doctor/healthchecks/xcode.js
index 0cd01ded7..74ac04a7c 100644
--- a/packages/cli/src/commands/doctor/healthchecks/xcode.js
+++ b/packages/cli/src/commands/doctor/healthchecks/xcode.js
@@ -3,17 +3,17 @@ import Ora from 'ora';
 import versionRanges from '../versionRanges';
 import {doesSoftwareNeedToBeFixed} from '../checkInstallation';
 import {logManualInstallation} from './common';
-import type {EnvironmentInfo} from '../types';
+import type {EnvironmentInfo, HealthCheckInterface} from '../types';
 
-export default {
+export default ({
   label: 'Xcode',
-  getDiagnostics: ({IDEs}: EnvironmentInfo) => ({
+  getDiagnostics: async ({IDEs}: EnvironmentInfo) => ({
     needsToBeFixed: doesSoftwareNeedToBeFixed({
       version: IDEs.Xcode.version.split('/')[0],
       versionRange: versionRanges.XCODE,
     }),
   }),
-  runAutomaticFix: ({loader}: {loader: typeof Ora}) => {
+  runAutomaticFix: async ({loader}: {loader: typeof Ora}) => {
     loader.info();
 
     logManualInstallation({
@@ -21,4 +21,4 @@ export default {
       url: 'https://developer.apple.com/xcode/',
     });
   },
-};
+}: HealthCheckInterface);
diff --git a/packages/cli/src/commands/doctor/runAutomaticFix.js b/packages/cli/src/commands/doctor/runAutomaticFix.js
index 561f054a1..f954dd9b7 100644
--- a/packages/cli/src/commands/doctor/runAutomaticFix.js
+++ b/packages/cli/src/commands/doctor/runAutomaticFix.js
@@ -18,10 +18,10 @@ export default async ({
   stats,
   loader,
   environmentInfo,
-}:{
+}: {
   healthchecks: any,
   automaticFixLevel: $Values<typeof AUTOMATIC_FIX_LEVELS>,
-  stats:{errors: any, warnings: any},
+  stats: {errors: any, warnings: any},
   loader: typeof ora,
   environmentInfo: EnvironmentInfo,
 }) => {
diff --git a/packages/cli/src/commands/doctor/types.js b/packages/cli/src/commands/doctor/types.js
index 9a58a8cd9..3793e8d9b 100644
--- a/packages/cli/src/commands/doctor/types.js
+++ b/packages/cli/src/commands/doctor/types.js
@@ -1,4 +1,6 @@
 // @flow
+import Ora from 'ora';
+
 export type EnvironmentInfo = {
   System: {
     OS: string,
@@ -62,3 +64,16 @@ export type EnvironmentInfo = {
     },
   },
 };
+
+export type HealthCheckInterface = {
+  label: string,
+  visible?: boolean | void,
+  isRequired?: boolean,
+  getDiagnostics: (
+    environmentInfo: EnvironmentInfo,
+  ) => Promise<{version?: string, needsToBeFixed: boolean | string}>,
+  runAutomaticFix: (args: {
+    loader: typeof Ora,
+    environmentInfo: EnvironmentInfo,
+  }) => Promise<void> | void,
+};