Inline fbjs/lib/emptyFunction (#13054)

packages/events/SyntheticEvent.js

@@ -7,7 +7,6 @@
 
 /* eslint valid-typeof: 0 */
 
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import invariant from 'fbjs/lib/invariant';
 import warning from 'fbjs/lib/warning';
 
@@ -32,7 +31,9 @@ const EventInterface = {
   type: null,
   target: null,
   // currentTarget is set when dispatching; no use in copying it here
-  currentTarget: emptyFunction.thatReturnsNull,
+  currentTarget: function() {
+    return null;
+  },
   eventPhase: null,
   bubbles: null,
   cancelable: null,
@@ -43,6 +44,14 @@ const EventInterface = {
   isTrusted: null,
 };
 
+function functionThatReturnsTrue() {
+  return true;
+}
+
+function functionThatReturnsFalse() {
+  return false;
+}
+
 /**
  * Synthetic events are dispatched by event plugins, typically in response to a
  * top-level event delegation handler.
@@ -103,11 +112,11 @@ function SyntheticEvent(
       ? nativeEvent.defaultPrevented
       : nativeEvent.returnValue === false;
   if (defaultPrevented) {
-    this.isDefaultPrevented = emptyFunction.thatReturnsTrue;
+    this.isDefaultPrevented = functionThatReturnsTrue;
   } else {
-    this.isDefaultPrevented = emptyFunction.thatReturnsFalse;
+    this.isDefaultPrevented = functionThatReturnsFalse;
   }
-  this.isPropagationStopped = emptyFunction.thatReturnsFalse;
+  this.isPropagationStopped = functionThatReturnsFalse;
   return this;
 }
 
@@ -124,7 +133,7 @@ Object.assign(SyntheticEvent.prototype, {
     } else if (typeof event.returnValue !== 'unknown') {
       event.returnValue = false;
     }
-    this.isDefaultPrevented = emptyFunction.thatReturnsTrue;
+    this.isDefaultPrevented = functionThatReturnsTrue;
   },
 
   stopPropagation: function() {
@@ -144,7 +153,7 @@ Object.assign(SyntheticEvent.prototype, {
       event.cancelBubble = true;
     }
 
-    this.isPropagationStopped = emptyFunction.thatReturnsTrue;
+    this.isPropagationStopped = functionThatReturnsTrue;
   },
 
   /**
@@ -153,7 +162,7 @@ Object.assign(SyntheticEvent.prototype, {
    * won't be added back into the pool.
    */
   persist: function() {
-    this.isPersistent = emptyFunction.thatReturnsTrue;
+    this.isPersistent = functionThatReturnsTrue;
   },
 
   /**
@@ -161,7 +170,7 @@ Object.assign(SyntheticEvent.prototype, {
    *
    * @return {boolean} True if this should not be released, false otherwise.
    */
-  isPersistent: emptyFunction.thatReturnsFalse,
+  isPersistent: functionThatReturnsFalse,
 
   /**
    * `PooledClass` looks for `destructor` on each instance it releases.
@@ -191,12 +200,12 @@ Object.assign(SyntheticEvent.prototype, {
       Object.defineProperty(
         this,
         'preventDefault',
-        getPooledWarningPropertyDefinition('preventDefault', emptyFunction),
+        getPooledWarningPropertyDefinition('preventDefault', () => {}),
       );
       Object.defineProperty(
         this,
         'stopPropagation',
-        getPooledWarningPropertyDefinition('stopPropagation', emptyFunction),
+        getPooledWarningPropertyDefinition('stopPropagation', () => {}),
       );
     }
   },

packages/react-dom/src/__tests__/ReactDOMInput-test.js

@@ -9,7 +9,7 @@
 
 'use strict';
 
-const emptyFunction = require('fbjs/lib/emptyFunction');
+function emptyFunction() {}
 
 describe('ReactDOMInput', () => {
   let React;

packages/react-dom/src/__tests__/ReactDOMTextarea-test.js

@@ -9,7 +9,7 @@
 
 'use strict';
 
-const emptyFunction = require('fbjs/lib/emptyFunction');
+function emptyFunction() {}
 
 describe('ReactDOMTextarea', () => {
   let React;

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

@@ -10,7 +10,6 @@
 // TODO: direct imports like some-package/src/* are bad. Fix me.
 import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
 import {registrationNameModules} from 'events/EventPluginRegistry';
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import warning from 'fbjs/lib/warning';
 
 import * as DOMPropertyOperations from './DOMPropertyOperations';
@@ -63,7 +62,7 @@ const HTML = '__html';
 
 const {html: HTML_NAMESPACE} = Namespaces;
 
-let getStack = emptyFunction.thatReturns('');
+let getStack = () => '';
 
 let warnedUnknownTags;
 let suppressHydrationWarning;
@@ -232,6 +231,8 @@ function getOwnerDocumentFromRootContainer(
     : rootContainerElement.ownerDocument;
 }
 
+function noop() {}
+
 function trapClickOnNonInteractiveElement(node: HTMLElement) {
   // Mobile Safari does not fire properly bubble click events on
   // non-interactive elements, which means delegated click listeners do not
@@ -242,7 +243,7 @@ function trapClickOnNonInteractiveElement(node: HTMLElement) {
   // bookkeeping for it. Not sure if we need to clear it when the listener is
   // removed.
   // TODO: Only do this for the relevant Safaris maybe?
-  node.onclick = emptyFunction;
+  node.onclick = noop;
 }
 
 function setInitialDOMProperties(

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

@@ -5,13 +5,12 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import warning from 'fbjs/lib/warning';
 // TODO: direct imports like some-package/src/* are bad. Fix me.
 import ReactDebugCurrentFiber from 'react-reconciler/src/ReactDebugCurrentFiber';
 
 const {getCurrentFiberStackAddendum} = ReactDebugCurrentFiber;
-let validateDOMNesting = emptyFunction;
+let validateDOMNesting = () => {};
 
 if (__DEV__) {
   // This validation code was written based on the HTML5 parsing spec:

packages/react-dom/src/server/ReactPartialRenderer.js

@@ -15,7 +15,6 @@ import type {
 } from 'shared/ReactTypes';
 
 import React from 'react';
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import emptyObject from 'fbjs/lib/emptyObject';
 import invariant from 'fbjs/lib/invariant';
 import lowPriorityWarning from 'shared/lowPriorityWarning';
@@ -66,8 +65,8 @@ const toArray = ((React.Children.toArray: any): toArrayType);
 let currentDebugStack;
 let currentDebugElementStack;
 
-let getStackAddendum = emptyFunction.thatReturns('');
-let describeStackFrame = emptyFunction.thatReturns('');
+let getStackAddendum = () => '';
+let describeStackFrame = element => '';
 
 let validatePropertiesInDevelopment = (type, props) => {};
 let setCurrentDebugStack = (stack: Array<Frame>) => {};

packages/react-dom/src/shared/warnValidStyle.js

@@ -5,10 +5,9 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import warning from 'fbjs/lib/warning';
 
-let warnValidStyle = emptyFunction;
+let warnValidStyle = () => {};
 
 if (__DEV__) {
   // 'msTransform' is correct, but the other prefixes should be capitalized

packages/react/src/ReactChildren.js

@@ -5,7 +5,6 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-import emptyFunction from 'fbjs/lib/emptyFunction';
 import invariant from 'fbjs/lib/invariant';
 import warning from 'fbjs/lib/warning';
 import {
@@ -292,12 +291,7 @@ function mapSingleChildIntoContext(bookKeeping, child, childKey) {
 
   let mappedChild = func.call(context, child, bookKeeping.count++);
   if (Array.isArray(mappedChild)) {
-    mapIntoWithKeyPrefixInternal(
-      mappedChild,
-      result,
-      childKey,
-      emptyFunction.thatReturnsArgument,
-    );
+    mapIntoWithKeyPrefixInternal(mappedChild, result, childKey, c => c);
   } else if (mappedChild != null) {
     if (isValidElement(mappedChild)) {
       mappedChild = cloneAndReplaceKey(
@@ -362,7 +356,7 @@ function mapChildren(children, func, context) {
  * @return {number} The number of children.
  */
 function countChildren(children) {
-  return traverseAllChildren(children, emptyFunction.thatReturnsNull, null);
+  return traverseAllChildren(children, () => null, null);
 }
 
 /**
@@ -373,12 +367,7 @@ function countChildren(children) {
  */
 function toArray(children) {
   const result = [];
-  mapIntoWithKeyPrefixInternal(
-    children,
-    result,
-    null,
-    emptyFunction.thatReturnsArgument,
-  );
+  mapIntoWithKeyPrefixInternal(children, result, null, child => child);
   return result;
 }