[flow] enable exact_empty_objects

packages/react-client/src/ReactFlightClient.js

@@ -393,7 +393,9 @@ function createElement(
     // We don't really need to add any of these but keeping them for good measure.
     // Unfortunately, _store is enumerable in jest matchers so for equality to
     // work, I need to keep it or make _store non-enumerable in the other file.
-    element._store = {};
+    element._store = ({}: {
+      validated?: boolean,
+    });
     Object.defineProperty(element._store, 'validated', {
       configurable: false,
       enumerable: false,

packages/react-debug-tools/src/ReactDebugHooks.js

@@ -524,7 +524,7 @@ function buildTree(
   readHookLog: Array<HookLogEntry>,
   includeHooksSource: boolean,
 ): HooksTree {
-  const rootChildren = [];
+  const rootChildren: Array<HooksNode> = [];
   let prevStack = null;
   let levelChildren = rootChildren;
   let nativeHookID = 0;
@@ -557,7 +557,7 @@ function buildTree(
       // The remaining part of the new stack are custom hooks. Push them
       // to the tree.
       for (let j = stack.length - commonSteps - 1; j >= 1; j--) {
-        const children = [];
+        const children: Array<HooksNode> = [];
         const stackFrame = stack[j];
         const levelChild: HooksNode = {
           id: null,

packages/react-devtools-shared/src/backend/NativeStyleEditor/setupNativeStyleEditor.js

@@ -170,7 +170,7 @@ function measureStyle(
 }
 
 function shallowClone(object: Object): Object {
-  const cloned = {};
+  const cloned: {[string]: $FlowFixMe} = {};
   for (const n in object) {
     cloned[n] = object[n];
   }

packages/react-devtools-shared/src/backend/console.js

@@ -79,7 +79,7 @@ const injectedRenderers: Map<
 > = new Map();
 
 let targetConsole: Object = console;
-let targetConsoleMethods = {};
+let targetConsoleMethods: {[string]: $FlowFixMe} = {};
 for (const method in console) {
   targetConsoleMethods[method] = console[method];
 }
@@ -97,7 +97,7 @@ export function dangerous_setTargetConsoleForTesting(
 ): void {
   targetConsole = targetConsoleForTesting;
 
-  targetConsoleMethods = {};
+  targetConsoleMethods = ({}: {[string]: $FlowFixMe});
   for (const method in targetConsole) {
     targetConsoleMethods[method] = console[method];
   }
@@ -179,7 +179,7 @@ export function patch({
       return;
     }
 
-    const originalConsoleMethods = {};
+    const originalConsoleMethods: {[string]: $FlowFixMe} = {};
 
     unpatchFn = () => {
       for (const method in originalConsoleMethods) {
@@ -318,7 +318,7 @@ export function patchForStrictMode() {
       return;
     }
 
-    const originalConsoleMethods = {};
+    const originalConsoleMethods: {[string]: $FlowFixMe} = {};
 
     unpatchForStrictModeFn = () => {
       for (const method in originalConsoleMethods) {

packages/react-devtools-shared/src/backend/legacy/renderer.js

@@ -785,7 +785,7 @@ export function attach(
 
       let owner = element._owner;
       if (owner) {
-        owners = [];
+        owners = ([]: Array<SerializedElement>);
         while (owner != null) {
           owners.push({
             displayName: getData(owner).displayName || 'Unknown',
@@ -807,8 +807,8 @@ export function attach(
     }
 
     // Not implemented
-    const errors = [];
-    const warnings = [];
+    const errors: Array<[string, number]> = [];
+    const warnings: Array<[string, number]> = [];
 
     return {
       id,

packages/react-devtools-shared/src/backend/legacy/utils.js

@@ -22,7 +22,7 @@ export function decorateMany(
   source: Object,
   fns: {[attr: string]: Function, ...},
 ): Object {
-  const olds = {};
+  const olds: {[string]: $FlowFixMe} = {};
   for (const name in fns) {
     olds[name] = decorate(source, name, fns[name]);
   }

packages/react-devtools-shared/src/backend/profilingHooks.js

@@ -52,7 +52,7 @@ let supportsUserTiming =
 let supportsUserTimingV3 = false;
 if (supportsUserTiming) {
   const CHECK_V3_MARK = '__v3';
-  const markOptions = {};
+  const markOptions = ({}: {startTime?: number});
   Object.defineProperty(markOptions, 'startTime', {
     get: function() {
       supportsUserTimingV3 = true;

packages/react-devtools-shared/src/backend/renderer.js

@@ -3252,7 +3252,7 @@ export function attach(
 
     let owners = null;
     if (_debugOwner) {
-      owners = [];
+      owners = ([]: Array<SerializedElement>);
       let owner: null | Fiber = _debugOwner;
       while (owner !== null) {
         owners.push(fiberToSerializedElement(owner));
@@ -3265,7 +3265,7 @@ export function attach(
 
     let hooks = null;
     if (usesHooks) {
-      const originalConsoleMethods = {};
+      const originalConsoleMethods: {[string]: $FlowFixMe} = {};
 
       // Temporarily disable all console logging before re-running the hook.
       for (const method in console) {

packages/react-devtools-shared/src/backend/utils.js

@@ -20,8 +20,8 @@ export function cleanForBridge(
   path?: Array<string | number> = [],
 ): DehydratedData | null {
   if (data !== null) {
-    const cleanedPaths = [];
-    const unserializablePaths = [];
+    const cleanedPaths: Array<Array<string | number>> = [];
+    const unserializablePaths: Array<Array<string | number>> = [];
     const cleanedData = dehydrate(
       data,
       cleanedPaths,

packages/react-devtools-shared/src/devtools/utils.js

@@ -198,7 +198,7 @@ const STACK_SOURCE_LOCATION = /([^\s]+) \((.+):(.+):(.+)\)/;
 export function stackToComponentSources(
   stack: string,
 ): Array<[string, ?Stack]> {
-  const out = [];
+  const out: Array<[string, ?Stack]> = [];
   stack
     .split(STACK_DELIMETER)
     .slice(1)

packages/react-devtools-shared/src/devtools/views/Components/types.js

@@ -125,14 +125,16 @@ export type InspectedElement = {
 
 // TODO: Add profiling type
 
+type Data =
+  | string
+  | Dehydrated
+  | Unserializable
+  | Array<Dehydrated>
+  | Array<Unserializable>
+  | {[string]: Data};
+
 export type DehydratedData = {
   cleaned: Array<Array<string | number>>,
-  data:
-    | string
-    | Dehydrated
-    | Unserializable
-    | Array<Dehydrated>
-    | Array<Unserializable>
-    | {[key: string]: string | Dehydrated | Unserializable, ...},
+  data: Data,
   unserializable: Array<Array<string | number>>,
 };

packages/react-devtools-shared/src/devtools/views/Profiler/CommitTreeBuilder.js

@@ -150,6 +150,7 @@ function updateTree(
 
   // Clone nodes before mutating them so edits don't affect them.
   const getClonedNode = (id: number): CommitTreeNode => {
+    // $FlowFixMe[prop-missing] - recommended fix is to use object spread operator
     const clonedNode = ((Object.assign(
       {},
       nodes.get(id),

packages/react-devtools-shared/src/devtools/views/utils.js

@@ -134,7 +134,7 @@ export function serializeDataForCopy(props: Object): string {
 
 export function serializeHooksForCopy(hooks: HooksTree | null): string {
   // $FlowFixMe "HooksTree is not an object"
-  const cloned = Object.assign([], hooks);
+  const cloned = Object.assign(([]: Array<any>), hooks);
 
   const queue = [...cloned];
 

packages/react-devtools-shared/src/hook.js

@@ -29,7 +29,7 @@ export function installHook(target: any): DevToolsHook | null {
   }
 
   let targetConsole: Object = console;
-  let targetConsoleMethods = {};
+  let targetConsoleMethods: {[string]: $FlowFixMe} = {};
   for (const method in console) {
     targetConsoleMethods[method] = console[method];
   }
@@ -39,7 +39,7 @@ export function installHook(target: any): DevToolsHook | null {
   ): void {
     targetConsole = targetConsoleForTesting;
 
-    targetConsoleMethods = {};
+    targetConsoleMethods = ({}: {[string]: $FlowFixMe});
     for (const method in targetConsole) {
       targetConsoleMethods[method] = console[method];
     }
@@ -250,7 +250,7 @@ export function installHook(target: any): DevToolsHook | null {
       return;
     }
 
-    const originalConsoleMethods = {};
+    const originalConsoleMethods: {[string]: $FlowFixMe} = {};
 
     unpatchFn = () => {
       for (const method in originalConsoleMethods) {
@@ -516,9 +516,9 @@ export function installHook(target: any): DevToolsHook | null {
   }
 
   // TODO: More meaningful names for "rendererInterfaces" and "renderers".
-  const fiberRoots = {};
+  const fiberRoots: {[RendererID]: Set<mixed>} = {};
   const rendererInterfaces = new Map();
-  const listeners = {};
+  const listeners: {[string]: Array<Handler>} = {};
   const renderers = new Map();
 
   const hook: DevToolsHook = {

packages/react-devtools-shared/src/hooks/astUtils.js

@@ -362,7 +362,7 @@ function getPotentialHookDeclarationsFromAST(sourceAST: File): NodePath[] {
 export function getHookNamesMappingFromAST(
   sourceAST: File,
 ): $ReadOnlyArray<{name: string, start: Position}> {
-  const hookStack = [];
+  const hookStack: Array<{name: string, start: $FlowFixMe}> = [];
   const hookNames = [];
   const pushFrame = (name: string, node: Node) => {
     const nameInfo = {name, start: {...node.loc.start}};

packages/react-devtools-shared/src/hooks/generateHookMap.js

@@ -63,7 +63,7 @@ export function generateHookMap(sourceAST: File): HookMap {
   const hookNamesMapping = getHookNamesMappingFromAST(sourceAST);
   const namesMap: Map<string, number> = new Map();
   const names = [];
-  const mappings = [];
+  const mappings: Array<HookMapLine> = [];
 
   let currentLine = null;
   hookNamesMapping.forEach(({name, start}) => {

packages/react-devtools-shared/src/hydration.js

@@ -16,7 +16,7 @@ import {
   setInObject,
 } from './utils';
 
-import type {DehydratedData} from 'react-devtools-shared/src/devtools/views/Components/types';
+import type {DehydratedData} from './devtools/views/Components/types';
 
 export const meta = {
   inspectable: (Symbol('inspectable'): symbol),
@@ -124,13 +124,7 @@ export function dehydrate(
   path: Array<string | number>,
   isPathAllowed: (path: Array<string | number>) => boolean,
   level?: number = 0,
-):
-  | string
-  | Dehydrated
-  | Unserializable
-  | Array<Dehydrated>
-  | Array<Unserializable>
-  | {[key: string]: string | Dehydrated | Unserializable, ...} {
+): $PropertyType<DehydratedData, 'data'> {
   const type = getDataType(data);
 
   let isPathAllowedCheck;
@@ -304,7 +298,9 @@ export function dehydrate(
       if (level >= LEVEL_THRESHOLD && !isPathAllowedCheck) {
         return createDehydrated(type, true, data, cleaned, path);
       } else {
-        const object = {};
+        const object: {
+          [string]: $PropertyType<DehydratedData, 'data'>,
+        } = {};
         getAllEnumerableKeys(data).forEach(key => {
           const name = key.toString();
           object[name] = dehydrate(

packages/react-devtools-shell/src/app/InspectableElements/CircularReferences.js

@@ -14,8 +14,15 @@ const arrayTwo = [];
 arrayTwo.push(arrayOne);
 arrayOne.push(arrayTwo);
 
-const objectOne = {};
-const objectTwo = {objectOne};
+type ObjectOne = {
+  objectTwo?: ObjectTwo,
+};
+type ObjectTwo = {
+  objectOne: ObjectOne,
+};
+
+const objectOne: ObjectOne = {};
+const objectTwo: ObjectTwo = {objectOne};
 objectOne.objectTwo = objectTwo;
 
 export default function CircularReferences(): React.Node {

packages/react-devtools-shell/src/app/index.js

@@ -33,7 +33,7 @@ ignoreErrors([
 ignoreWarnings(['Warning: componentWillReceiveProps has been renamed']);
 ignoreLogs([]);
 
-const unmountFunctions = [];
+const unmountFunctions: Array<() => void | boolean> = [];
 
 function createContainer() {
   const container = document.createElement('div');

packages/react-devtools-timeline/src/TimelineSearchContext.js

@@ -40,7 +40,7 @@ type Action =
 
 type Dispatch = (action: Action) => void;
 
-const EMPTY_ARRAY = [];
+const EMPTY_ARRAY: Array<ReactComponentMeasure> = [];
 
 function reducer(state: State, action: Action): State {
   let {searchIndex, searchRegExp, searchResults, searchText} = state;

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

@@ -672,7 +672,7 @@ export function diffProperties(
       for (styleName in lastStyle) {
         if (lastStyle.hasOwnProperty(styleName)) {
           if (!styleUpdates) {
-            styleUpdates = {};
+            styleUpdates = ({}: {[string]: $FlowFixMe});
           }
           styleUpdates[styleName] = '';
         }
@@ -725,7 +725,7 @@ export function diffProperties(
             (!nextProp || !nextProp.hasOwnProperty(styleName))
           ) {
             if (!styleUpdates) {
-              styleUpdates = {};
+              styleUpdates = ({}: {[string]: string});
             }
             styleUpdates[styleName] = '';
           }
@@ -737,7 +737,7 @@ export function diffProperties(
             lastProp[styleName] !== nextProp[styleName]
           ) {
             if (!styleUpdates) {
-              styleUpdates = {};
+              styleUpdates = ({}: {[string]: $FlowFixMe});
             }
             styleUpdates[styleName] = nextProp[styleName];
           }

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

@@ -792,6 +792,7 @@ export function getResource(
 function preloadPropsFromRawProps(
   rawBorrowedProps: PreloadQualifyingProps,
 ): PreloadProps {
+  // $FlowFixMe[prop-missing] - recommended fix is to use object spread operator
   return Object.assign({}, rawBorrowedProps);
 }
 
@@ -805,6 +806,7 @@ function titlePropsFromRawProps(
 }
 
 function stylePropsFromRawProps(rawProps: StyleQualifyingProps): StyleProps {
+  // $FlowFixMe[prop-missing] - recommended fix is to use object spread operator
   const props: StyleProps = Object.assign({}, rawProps);
   props['data-precedence'] = rawProps.precedence;
   props.precedence = null;
@@ -813,6 +815,7 @@ function stylePropsFromRawProps(rawProps: StyleQualifyingProps): StyleProps {
 }
 
 function scriptPropsFromRawProps(rawProps: ScriptQualifyingProps): ScriptProps {
+  // $FlowFixMe[prop-missing] - recommended fix is to use object spread operator
   const props: ScriptProps = Object.assign({}, rawProps);
   return props;
 }
@@ -1318,7 +1321,9 @@ function acquireScriptResource(resource: ScriptResource): Instance {
 }
 
 function attachLoadListeners(instance: Instance, resource: StyleResource) {
-  const listeners = {};
+  const listeners: {
+    [string]: () => mixed,
+  } = {};
   listeners.load = onResourceLoad.bind(
     null,
     instance,

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

@@ -77,7 +77,7 @@ function updateOptions(
 
   if (multiple) {
     const selectedValues = (propValue: Array<string>);
-    const selectedValue = {};
+    const selectedValue: {[string]: boolean} = {};
     for (let i = 0; i < selectedValues.length; i++) {
       // Prefix to avoid chaos with special keys.
       selectedValue['$' + selectedValues[i]] = true;

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

@@ -434,7 +434,7 @@ if (__DEV__) {
     return null;
   };
 
-  const didWarn = {};
+  const didWarn: {[string]: boolean} = {};
 
   validateDOMNesting = function(
     childTag: ?string,