Flow: complete types first migration

packages/react-dom-bindings/src/client/ReactDOMInput.js

@@ -59,7 +59,7 @@ function isControlled(props) {
  * See http://www.w3.org/TR/2012/WD-html5-20121025/the-input-element.html
  */
 
-export function getHostProps(element: Element, props: Object) {
+export function getHostProps(element: Element, props: Object): Object {
   const node = ((element: any): InputWithWrapperState);
   const checked = props.checked;
 

packages/react-dom-bindings/src/client/ReactDOMSelect.js

@@ -134,7 +134,7 @@ function updateOptions(
  * selected.
  */
 
-export function getHostProps(element: Element, props: Object) {
+export function getHostProps(element: Element, props: Object): Object {
   return assign({}, props, {
     value: undefined,
   });

packages/react-dom-bindings/src/client/ReactDOMTextarea.js

@@ -37,7 +37,7 @@ type TextAreaWithWrapperState = HTMLTextAreaElement & {
  * `defaultValue` if specified, or the children content (deprecated).
  */
 
-export function getHostProps(element: Element, props: Object) {
+export function getHostProps(element: Element, props: Object): Object {
   const node = ((element: any): TextAreaWithWrapperState);
 
   if (props.dangerouslySetInnerHTML != null) {

packages/react-dom-bindings/src/client/setInnerHTML.js

@@ -21,7 +21,10 @@ let reusableSVGContainer;
  * @param {string} html
  * @internal
  */
-const setInnerHTML = createMicrosoftUnsafeLocalFunction(function(
+const setInnerHTML: (
+  node: Element,
+  html: {valueOf(): {toString(): string, ...}, ...},
+) => void = createMicrosoftUnsafeLocalFunction(function(
   node: Element,
   html: {valueOf(): {toString(): string, ...}, ...},
 ): void {

packages/react-dom-bindings/src/events/EventRegistry.js

@@ -21,15 +21,19 @@ if (enableCreateEventHandleAPI) {
 /**
  * Mapping from registration name to event name
  */
-export const registrationNameDependencies = {};
+export const registrationNameDependencies: {
+  [registrationName: string]: Array<DOMEventName>,
+} = {};
 
 /**
  * Mapping from lowercase registration names to the properly cased version,
  * used to warn in the case of missing event handlers. Available
  * only in __DEV__.
  * @type {Object}
  */
-export const possibleRegistrationNames = __DEV__ ? {} : (null: any);
+export const possibleRegistrationNames: {
+  [lowerCasedName: string]: string,
+} = __DEV__ ? {} : (null: any);
 // Trust the developer to only use possibleRegistrationNames in __DEV__
 
 export function registerTwoPhaseEvent(

packages/react-dom-bindings/src/events/ReactDOMEventListener.js

@@ -8,7 +8,7 @@
  */
 
 import type {AnyNativeEvent} from '../events/PluginModuleType';
-import type {FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
+import type {Fiber, FiberRoot} from 'react-reconciler/src/ReactInternalTypes';
 import type {Container, SuspenseInstance} from '../client/ReactDOMHostConfig';
 import type {DOMEventName} from '../events/DOMEventNames';
 import {enableCapturePhaseSelectiveHydrationWithoutDiscreteEventReplay} from 'shared/ReactFeatureFlags';
@@ -58,15 +58,15 @@ import {isRootDehydrated} from 'react-reconciler/src/ReactFiberShellHydration';
 const {ReactCurrentBatchConfig} = ReactSharedInternals;
 
 // TODO: can we stop exporting these?
-export let _enabled = true;
+export let _enabled: boolean = true;
 
 // This is exported in FB builds for use by legacy FB layer infra.
 // We'd like to remove this but it's not clear if this is safe.
-export function setEnabled(enabled: ?boolean) {
+export function setEnabled(enabled: ?boolean): void {
   _enabled = !!enabled;
 }
 
-export function isEnabled() {
+export function isEnabled(): boolean {
   return _enabled;
 }
 
@@ -348,7 +348,7 @@ function dispatchEventWithEnableCapturePhaseSelectiveHydrationWithoutDiscreteEve
   );
 }
 
-export let return_targetInst = null;
+export let return_targetInst: null | Fiber = null;
 
 // Returns a SuspenseInstance or Container if it's blocked.
 // The return_targetInst field above is conceptually part of the return value.

packages/react-dom-bindings/src/events/SyntheticEvent.js

@@ -16,7 +16,6 @@ import getEventCharCode from './getEventCharCode';
 
 type EventInterfaceType = {
   [propName: string]: 0 | ((event: {[propName: string]: mixed, ...}) => mixed),
-  ...,
 };
 
 function functionThatReturnsTrue() {
@@ -153,14 +152,16 @@ const EventInterface = {
   defaultPrevented: 0,
   isTrusted: 0,
 };
-export const SyntheticEvent = createSyntheticEvent(EventInterface);
+export const SyntheticEvent: $FlowFixMe = createSyntheticEvent(EventInterface);
 
 const UIEventInterface: EventInterfaceType = {
   ...EventInterface,
   view: 0,
   detail: 0,
 };
-export const SyntheticUIEvent = createSyntheticEvent(UIEventInterface);
+export const SyntheticUIEvent: $FlowFixMe = createSyntheticEvent(
+  UIEventInterface,
+);
 
 let lastMovementX;
 let lastMovementY;
@@ -225,7 +226,9 @@ const MouseEventInterface: EventInterfaceType = {
     return lastMovementY;
   },
 };
-export const SyntheticMouseEvent = createSyntheticEvent(MouseEventInterface);
+export const SyntheticMouseEvent: $FlowFixMe = createSyntheticEvent(
+  MouseEventInterface,
+);
 
 /**
  * @interface DragEvent
@@ -235,7 +238,9 @@ const DragEventInterface: EventInterfaceType = {
   ...MouseEventInterface,
   dataTransfer: 0,
 };
-export const SyntheticDragEvent = createSyntheticEvent(DragEventInterface);
+export const SyntheticDragEvent: $FlowFixMe = createSyntheticEvent(
+  DragEventInterface,
+);
 
 /**
  * @interface FocusEvent
@@ -245,7 +250,9 @@ const FocusEventInterface: EventInterfaceType = {
   ...UIEventInterface,
   relatedTarget: 0,
 };
-export const SyntheticFocusEvent = createSyntheticEvent(FocusEventInterface);
+export const SyntheticFocusEvent: $FlowFixMe = createSyntheticEvent(
+  FocusEventInterface,
+);
 
 /**
  * @interface Event
@@ -258,7 +265,7 @@ const AnimationEventInterface: EventInterfaceType = {
   elapsedTime: 0,
   pseudoElement: 0,
 };
-export const SyntheticAnimationEvent = createSyntheticEvent(
+export const SyntheticAnimationEvent: $FlowFixMe = createSyntheticEvent(
   AnimationEventInterface,
 );
 
@@ -274,7 +281,7 @@ const ClipboardEventInterface: EventInterfaceType = {
       : window.clipboardData;
   },
 };
-export const SyntheticClipboardEvent = createSyntheticEvent(
+export const SyntheticClipboardEvent: $FlowFixMe = createSyntheticEvent(
   ClipboardEventInterface,
 );
 
@@ -286,7 +293,7 @@ const CompositionEventInterface: EventInterfaceType = {
   ...EventInterface,
   data: 0,
 };
-export const SyntheticCompositionEvent = createSyntheticEvent(
+export const SyntheticCompositionEvent: $FlowFixMe = createSyntheticEvent(
   CompositionEventInterface,
 );
 
@@ -487,7 +494,7 @@ const KeyboardEventInterface = {
     return 0;
   },
 };
-export const SyntheticKeyboardEvent = createSyntheticEvent(
+export const SyntheticKeyboardEvent: $FlowFixMe = createSyntheticEvent(
   KeyboardEventInterface,
 );
 
@@ -508,7 +515,7 @@ const PointerEventInterface = {
   pointerType: 0,
   isPrimary: 0,
 };
-export const SyntheticPointerEvent = createSyntheticEvent(
+export const SyntheticPointerEvent: $FlowFixMe = createSyntheticEvent(
   PointerEventInterface,
 );
 
@@ -527,7 +534,9 @@ const TouchEventInterface = {
   shiftKey: 0,
   getModifierState: getEventModifierState,
 };
-export const SyntheticTouchEvent = createSyntheticEvent(TouchEventInterface);
+export const SyntheticTouchEvent: $FlowFixMe = createSyntheticEvent(
+  TouchEventInterface,
+);
 
 /**
  * @interface Event
@@ -540,7 +549,7 @@ const TransitionEventInterface = {
   elapsedTime: 0,
   pseudoElement: 0,
 };
-export const SyntheticTransitionEvent = createSyntheticEvent(
+export const SyntheticTransitionEvent: $FlowFixMe = createSyntheticEvent(
   TransitionEventInterface,
 );
 
@@ -580,4 +589,6 @@ const WheelEventInterface = {
   // ~40 pixels, for DOM_DELTA_SCREEN (2) it is 87.5% of viewport size.
   deltaMode: 0,
 };
-export const SyntheticWheelEvent = createSyntheticEvent(WheelEventInterface);
+export const SyntheticWheelEvent: $FlowFixMe = createSyntheticEvent(
+  WheelEventInterface,
+);

packages/react-dom-bindings/src/events/forks/EventListener-www.js

@@ -16,15 +16,15 @@ export function addEventBubbleListener(
   target: EventTarget,
   eventType: string,
   listener: Function,
-) {
+): mixed {
   return EventListenerWWW.listen(target, eventType, listener);
 }
 
 export function addEventCaptureListener(
   target: EventTarget,
   eventType: string,
   listener: Function,
-) {
+): mixed {
   return EventListenerWWW.capture(target, eventType, listener);
 }
 
@@ -33,7 +33,7 @@ export function addEventCaptureListenerWithPassiveFlag(
   eventType: string,
   listener: Function,
   passive: boolean,
-) {
+): mixed {
   return EventListenerWWW.captureWithPassiveFlag(
     target,
     eventType,
@@ -47,7 +47,7 @@ export function addEventBubbleListenerWithPassiveFlag(
   eventType: string,
   listener: Function,
   passive: boolean,
-) {
+): mixed {
   return EventListenerWWW.bubbleWithPassiveFlag(
     target,
     eventType,

packages/react-dom/src/client/ReactDOM.js

@@ -8,7 +8,10 @@
  */
 
 import type {ReactNodeList} from 'shared/ReactTypes';
-import type {Container} from 'react-dom-bindings/src/client/ReactDOMHostConfig';
+import type {
+  Container,
+  PublicInstance,
+} from 'react-dom-bindings/src/client/ReactDOMHostConfig';
 import type {
   RootType,
   HydrateRootOptions,
@@ -125,7 +128,7 @@ function renderSubtreeIntoContainer(
   element: React$Element<any>,
   containerNode: Container,
   callback: ?Function,
-) {
+): React$Component<any, any> | PublicInstance | null {
   return unstable_renderSubtreeIntoContainer(
     parentComponent,
     element,
@@ -171,7 +174,7 @@ declare function flushSync<R>(fn: () => R): R;
 // eslint-disable-next-line no-redeclare
 declare function flushSync(): void;
 // eslint-disable-next-line no-redeclare
-function flushSync(fn) {
+function flushSync<R>(fn: (() => R) | void): R | void {
   if (__DEV__) {
     if (isAlreadyRendering()) {
       console.error(