events: convert var to let/const (#11714)

Author: raphamorim

packages/events/EventPluginHub.js

@@ -30,7 +30,7 @@ import type {AnyNativeEvent} from './PluginModuleType';
  * Internal queue of events that have accumulated their dispatches and are
  * waiting to have their dispatches executed.
  */
-var eventQueue: ?(Array<ReactSyntheticEvent> | ReactSyntheticEvent) = null;
+let eventQueue: ?(Array<ReactSyntheticEvent> | ReactSyntheticEvent) = null;
 
 /**
  * Dispatches an event and releases it back into the pool, unless persistent.
@@ -39,7 +39,7 @@ var eventQueue: ?(Array<ReactSyntheticEvent> | ReactSyntheticEvent) = null;
  * @param {boolean} simulated If the event is simulated (changes exn behavior)
  * @private
  */
-var executeDispatchesAndRelease = function(
+const executeDispatchesAndRelease = function(
   event: ReactSyntheticEvent,
   simulated: boolean,
 ) {
@@ -51,10 +51,10 @@ var executeDispatchesAndRelease = function(
     }
   }
 };
-var executeDispatchesAndReleaseSimulated = function(e) {
+const executeDispatchesAndReleaseSimulated = function(e) {
   return executeDispatchesAndRelease(e, true);
 };
-var executeDispatchesAndReleaseTopLevel = function(e) {
+const executeDispatchesAndReleaseTopLevel = function(e) {
   return executeDispatchesAndRelease(e, false);
 };
 
@@ -130,7 +130,7 @@ export const injection = {
  * @return {?function} The stored callback.
  */
 export function getListener(inst: Fiber, registrationName: string) {
-  var listener;
+  let listener;
 
   // TODO: shouldPreventMouseEvent is DOM-specific and definitely should not
   // live here; needs to be moved to a better place soon
@@ -170,12 +170,12 @@ export function extractEvents(
   nativeEvent: AnyNativeEvent,
   nativeEventTarget: EventTarget,
 ) {
-  var events;
-  for (var i = 0; i < plugins.length; i++) {
+  let events;
+  for (let i = 0; i < plugins.length; i++) {
     // Not every plugin in the ordering may be loaded at runtime.
-    var possiblePlugin: PluginModule<AnyNativeEvent> = plugins[i];
+    const possiblePlugin: PluginModule<AnyNativeEvent> = plugins[i];
     if (possiblePlugin) {
-      var extractedEvents = possiblePlugin.extractEvents(
+      const extractedEvents = possiblePlugin.extractEvents(
         topLevelType,
         targetInst,
         nativeEvent,
@@ -212,7 +212,7 @@ export function enqueueEvents(
 export function processEventQueue(simulated: boolean) {
   // Set `eventQueue` to null before processing it so that we can tell if more
   // events get enqueued while processing.
-  var processingEventQueue = eventQueue;
+  const processingEventQueue = eventQueue;
   eventQueue = null;
 
   if (!processingEventQueue) {

packages/events/EventPluginRegistry.js

@@ -20,17 +20,17 @@ import lowPriorityWarning from 'shared/lowPriorityWarning';
 type NamesToPlugins = {[key: PluginName]: PluginModule<AnyNativeEvent>};
 type EventPluginOrder = null | Array<PluginName>;
 
-var shouldWarnOnInjection = false;
+let shouldWarnOnInjection = false;
 
 /**
  * Injectable ordering of event plugins.
  */
-var eventPluginOrder: EventPluginOrder = null;
+let eventPluginOrder: EventPluginOrder = null;
 
 /**
  * Injectable mapping from names to event plugin modules.
  */
-var namesToPlugins: NamesToPlugins = {};
+const namesToPlugins: NamesToPlugins = {};
 
 export function enableWarningOnInjection() {
   shouldWarnOnInjection = true;
@@ -46,9 +46,9 @@ function recomputePluginOrdering(): void {
     // Wait until an `eventPluginOrder` is injected.
     return;
   }
-  for (var pluginName in namesToPlugins) {
-    var pluginModule = namesToPlugins[pluginName];
-    var pluginIndex = eventPluginOrder.indexOf(pluginName);
+  for (const pluginName in namesToPlugins) {
+    const pluginModule = namesToPlugins[pluginName];
+    const pluginIndex = eventPluginOrder.indexOf(pluginName);
     invariant(
       pluginIndex > -1,
       'EventPluginRegistry: Cannot inject event plugins that do not exist in ' +
@@ -65,8 +65,8 @@ function recomputePluginOrdering(): void {
       pluginName,
     );
     plugins[pluginIndex] = pluginModule;
-    var publishedEvents = pluginModule.eventTypes;
-    for (var eventName in publishedEvents) {
+    const publishedEvents = pluginModule.eventTypes;
+    for (const eventName in publishedEvents) {
       invariant(
         publishEventForPlugin(
           publishedEvents[eventName],
@@ -102,11 +102,11 @@ function publishEventForPlugin(
   );
   eventNameDispatchConfigs[eventName] = dispatchConfig;
 
-  var phasedRegistrationNames = dispatchConfig.phasedRegistrationNames;
+  const phasedRegistrationNames = dispatchConfig.phasedRegistrationNames;
   if (phasedRegistrationNames) {
-    for (var phaseName in phasedRegistrationNames) {
+    for (const phaseName in phasedRegistrationNames) {
       if (phasedRegistrationNames.hasOwnProperty(phaseName)) {
-        var phasedRegistrationName = phasedRegistrationNames[phaseName];
+        const phasedRegistrationName = phasedRegistrationNames[phaseName];
         publishRegistrationName(
           phasedRegistrationName,
           pluginModule,
@@ -149,7 +149,7 @@ function publishRegistrationName(
     pluginModule.eventTypes[eventName].dependencies;
 
   if (__DEV__) {
-    var lowerCasedName = registrationName.toLowerCase();
+    const lowerCasedName = registrationName.toLowerCase();
     possibleRegistrationNames[lowerCasedName] = registrationName;
 
     if (registrationName === 'onDoubleClick') {
@@ -243,12 +243,12 @@ export function injectEventPluginsByName(
     }
   }
 
-  var isOrderingDirty = false;
-  for (var pluginName in injectedNamesToPlugins) {
+  let isOrderingDirty = false;
+  for (const pluginName in injectedNamesToPlugins) {
     if (!injectedNamesToPlugins.hasOwnProperty(pluginName)) {
       continue;
     }
-    var pluginModule = injectedNamesToPlugins[pluginName];
+    const pluginModule = injectedNamesToPlugins[pluginName];
     if (
       !namesToPlugins.hasOwnProperty(pluginName) ||
       namesToPlugins[pluginName] !== pluginModule

packages/events/EventPluginUtils.js

@@ -45,19 +45,19 @@ export function isStartish(topLevelType) {
   return topLevelType === 'topMouseDown' || topLevelType === 'topTouchStart';
 }
 
-var validateEventDispatches;
+let validateEventDispatches;
 if (__DEV__) {
   validateEventDispatches = function(event) {
-    var dispatchListeners = event._dispatchListeners;
-    var dispatchInstances = event._dispatchInstances;
+    const dispatchListeners = event._dispatchListeners;
+    const dispatchInstances = event._dispatchInstances;
 
-    var listenersIsArr = Array.isArray(dispatchListeners);
-    var listenersLen = listenersIsArr
+    const listenersIsArr = Array.isArray(dispatchListeners);
+    const listenersLen = listenersIsArr
       ? dispatchListeners.length
       : dispatchListeners ? 1 : 0;
 
-    var instancesIsArr = Array.isArray(dispatchInstances);
-    var instancesLen = instancesIsArr
+    const instancesIsArr = Array.isArray(dispatchInstances);
+    const instancesLen = instancesIsArr
       ? dispatchInstances.length
       : dispatchInstances ? 1 : 0;
 
@@ -76,7 +76,7 @@ if (__DEV__) {
  * @param {*} inst Internal component instance
  */
 function executeDispatch(event, simulated, listener, inst) {
-  var type = event.type || 'unknown-event';
+  const type = event.type || 'unknown-event';
   event.currentTarget = getNodeFromInstance(inst);
   ReactErrorUtils.invokeGuardedCallbackAndCatchFirstError(
     type,
@@ -91,13 +91,13 @@ function executeDispatch(event, simulated, listener, inst) {
  * Standard/simple iteration through an event's collected dispatches.
  */
 export function executeDispatchesInOrder(event, simulated) {
-  var dispatchListeners = event._dispatchListeners;
-  var dispatchInstances = event._dispatchInstances;
+  const dispatchListeners = event._dispatchListeners;
+  const dispatchInstances = event._dispatchInstances;
   if (__DEV__) {
     validateEventDispatches(event);
   }
   if (Array.isArray(dispatchListeners)) {
-    for (var i = 0; i < dispatchListeners.length; i++) {
+    for (let i = 0; i < dispatchListeners.length; i++) {
       if (event.isPropagationStopped()) {
         break;
       }
@@ -124,13 +124,13 @@ export function executeDispatchesInOrder(event, simulated) {
  * true, or null if no listener returned true.
  */
 function executeDispatchesInOrderStopAtTrueImpl(event) {
-  var dispatchListeners = event._dispatchListeners;
-  var dispatchInstances = event._dispatchInstances;
+  const dispatchListeners = event._dispatchListeners;
+  const dispatchInstances = event._dispatchInstances;
   if (__DEV__) {
     validateEventDispatches(event);
   }
   if (Array.isArray(dispatchListeners)) {
-    for (var i = 0; i < dispatchListeners.length; i++) {
+    for (let i = 0; i < dispatchListeners.length; i++) {
       if (event.isPropagationStopped()) {
         break;
       }
@@ -151,7 +151,7 @@ function executeDispatchesInOrderStopAtTrueImpl(event) {
  * @see executeDispatchesInOrderStopAtTrueImpl
  */
 export function executeDispatchesInOrderStopAtTrue(event) {
-  var ret = executeDispatchesInOrderStopAtTrueImpl(event);
+  const ret = executeDispatchesInOrderStopAtTrueImpl(event);
   event._dispatchInstances = null;
   event._dispatchListeners = null;
   return ret;
@@ -170,16 +170,16 @@ export function executeDirectDispatch(event) {
   if (__DEV__) {
     validateEventDispatches(event);
   }
-  var dispatchListener = event._dispatchListeners;
-  var dispatchInstance = event._dispatchInstances;
+  const dispatchListener = event._dispatchListeners;
+  const dispatchInstance = event._dispatchInstances;
   invariant(
     !Array.isArray(dispatchListener),
     'executeDirectDispatch(...): Invalid `event`.',
   );
   event.currentTarget = dispatchListener
     ? getNodeFromInstance(dispatchInstance)
     : null;
-  var res = dispatchListener ? dispatchListener(event) : null;
+  const res = dispatchListener ? dispatchListener(event) : null;
   event.currentTarget = null;
   event._dispatchListeners = null;
   event._dispatchInstances = null;

packages/events/EventPropagators.js

@@ -23,7 +23,7 @@ type PropagationPhases = 'bubbled' | 'captured';
  * "phases" of propagation. This finds listeners by a given phase.
  */
 function listenerAtPhase(inst, event, propagationPhase: PropagationPhases) {
-  var registrationName =
+  const registrationName =
     event.dispatchConfig.phasedRegistrationNames[propagationPhase];
   return getListener(inst, registrationName);
 }
@@ -48,7 +48,7 @@ function accumulateDirectionalDispatches(inst, phase, event) {
   if (__DEV__) {
     warning(inst, 'Dispatching inst must not be null');
   }
-  var listener = listenerAtPhase(inst, event, phase);
+  const listener = listenerAtPhase(inst, event, phase);
   if (listener) {
     event._dispatchListeners = accumulateInto(
       event._dispatchListeners,
@@ -76,8 +76,8 @@ function accumulateTwoPhaseDispatchesSingle(event) {
  */
 function accumulateTwoPhaseDispatchesSingleSkipTarget(event) {
   if (event && event.dispatchConfig.phasedRegistrationNames) {
-    var targetInst = event._targetInst;
-    var parentInst = targetInst ? getParentInstance(targetInst) : null;
+    const targetInst = event._targetInst;
+    const parentInst = targetInst ? getParentInstance(targetInst) : null;
     traverseTwoPhase(parentInst, accumulateDirectionalDispatches, event);
   }
 }
@@ -89,8 +89,8 @@ function accumulateTwoPhaseDispatchesSingleSkipTarget(event) {
  */
 function accumulateDispatches(inst, ignoredDirection, event) {
   if (inst && event && event.dispatchConfig.registrationName) {
-    var registrationName = event.dispatchConfig.registrationName;
-    var listener = getListener(inst, registrationName);
+    const registrationName = event.dispatchConfig.registrationName;
+    const listener = getListener(inst, registrationName);
     if (listener) {
       event._dispatchListeners = accumulateInto(
         event._dispatchListeners,

packages/events/ReactControlledComponent.js

@@ -14,23 +14,23 @@ import {
 
 // Use to restore controlled state after a change event has fired.
 
-var fiberHostComponent = null;
+let fiberHostComponent = null;
 
-var ReactControlledComponentInjection = {
+const ReactControlledComponentInjection = {
   injectFiberControlledHostComponent: function(hostComponentImpl) {
     // The fiber implementation doesn't use dynamic dispatch so we need to
     // inject the implementation.
     fiberHostComponent = hostComponentImpl;
   },
 };
 
-var restoreTarget = null;
-var restoreQueue = null;
+let restoreTarget = null;
+let restoreQueue = null;
 
 function restoreStateOfTarget(target) {
   // We perform this translation at the end of the event loop so that we
   // always receive the correct fiber here
-  var internalInstance = getInstanceFromNode(target);
+  const internalInstance = getInstanceFromNode(target);
   if (!internalInstance) {
     // Unmounted
     return;
@@ -67,14 +67,14 @@ export function restoreStateIfNeeded() {
   if (!restoreTarget) {
     return;
   }
-  var target = restoreTarget;
-  var queuedTargets = restoreQueue;
+  const target = restoreTarget;
+  const queuedTargets = restoreQueue;
   restoreTarget = null;
   restoreQueue = null;
 
   restoreStateOfTarget(target);
   if (queuedTargets) {
-    for (var i = 0; i < queuedTargets.length; i++) {
+    for (let i = 0; i < queuedTargets.length; i++) {
       restoreStateOfTarget(queuedTargets[i]);
     }
   }

packages/events/ReactEventEmitterMixin.js

@@ -26,7 +26,7 @@ export function handleTopLevel(
   nativeEvent,
   nativeEventTarget,
 ) {
-  var events = extractEvents(
+  const events = extractEvents(
     topLevelType,
     targetInst,
     nativeEvent,

packages/events/ReactGenericBatching.js

@@ -14,11 +14,11 @@ import {restoreStateIfNeeded} from './ReactControlledComponent';
 // scheduled work and instead do synchronous work.
 
 // Defaults
-var fiberBatchedUpdates = function(fn, bookkeeping) {
+let fiberBatchedUpdates = function(fn, bookkeeping) {
   return fn(bookkeeping);
 };
 
-var isNestingBatched = false;
+let isNestingBatched = false;
 export function batchedUpdates(fn, bookkeeping) {
   if (isNestingBatched) {
     // If we are currently inside another batch, we need to wait until it
@@ -39,7 +39,7 @@ export function batchedUpdates(fn, bookkeeping) {
   }
 }
 
-var ReactGenericBatchingInjection = {
+const ReactGenericBatchingInjection = {
   injectFiberBatchedUpdates: function(_batchedUpdates) {
     fiberBatchedUpdates = _batchedUpdates;
   },