Remove keyMirror usage in JSTimers

Reviewed By: davidaurelio

Differential Revision: D3981015

fbshipit-source-id: 9ce7601038b7cdf8a7feb580380557ed84008397

Libraries/JavaScriptAppEngine/System/JSTimers/JSTimers.js

@@ -15,8 +15,11 @@
 // in dependencies. NativeModules > BatchedBridge > MessageQueue > JSTimersExecution
 const RCTTiming = require('NativeModules').Timing;
 const JSTimersExecution = require('JSTimersExecution');
+
 const parseErrorStack = require('parseErrorStack');
 
+import type {JSTimerType} from 'JSTimersExecution';
+
 // Returns a free index if one is available, and the next consecutive index otherwise.
 function _getFreeIndex(): number {
   let freeIndex = JSTimersExecution.timerIDs.indexOf(null);
@@ -26,7 +29,7 @@ function _getFreeIndex(): number {
   return freeIndex;
 }
 
-function _allocateCallback(func: Function, type: $Keys<typeof JSTimersExecution.Type>): number {
+function _allocateCallback(func: Function, type: JSTimerType): number {
   const id = JSTimersExecution.GUID++;
   const freeIndex = _getFreeIndex();
   JSTimersExecution.timerIDs[freeIndex] = id;
@@ -57,8 +60,7 @@ function _freeCallback(timerID: number) {
   if (index !== -1) {
     JSTimersExecution._clearIndex(index);
     const type = JSTimersExecution.types[index];
-    if (type !== JSTimersExecution.Type.setImmediate &&
+    if (type !== 'setImmediate' && type !== 'requestIdleCallback') {
-        type !== JSTimersExecution.Type.requestIdleCallback) {
       RCTTiming.deleteTimer(timerID);
     }
   }
@@ -75,8 +77,7 @@ const JSTimers = {
    * @param {number} duration Number of milliseconds.
    */
   setTimeout: function(func: Function, duration: number, ...args?: any): number {
-    const id = _allocateCallback(() => func.apply(undefined, args),
+    const id = _allocateCallback(() => func.apply(undefined, args), 'setTimeout');
-                                 JSTimersExecution.Type.setTimeout);
     RCTTiming.createTimer(id, duration || 0, Date.now(), /* recurring */ false);
     return id;
   },
@@ -86,8 +87,7 @@ const JSTimers = {
    * @param {number} duration Number of milliseconds.
    */
   setInterval: function(func: Function, duration: number, ...args?: any): number {
-    const id = _allocateCallback(() => func.apply(undefined, args),
+    const id = _allocateCallback(() => func.apply(undefined, args), 'setInterval');
-                                 JSTimersExecution.Type.setInterval);
     RCTTiming.createTimer(id, duration || 0, Date.now(), /* recurring */ true);
     return id;
   },
@@ -97,8 +97,7 @@ const JSTimers = {
    * current JavaScript execution loop.
    */
   setImmediate: function(func: Function, ...args?: any) {
-    const id = _allocateCallback(() => func.apply(undefined, args),
+    const id = _allocateCallback(() => func.apply(undefined, args), 'setImmediate');
-                                 JSTimersExecution.Type.setImmediate);
     JSTimersExecution.immediates.push(id);
     return id;
   },
@@ -107,7 +106,7 @@ const JSTimers = {
    * @param {function} func Callback to be invoked every frame.
    */
   requestAnimationFrame: function(func : Function) {
-    const id = _allocateCallback(func, JSTimersExecution.Type.requestAnimationFrame);
+    const id = _allocateCallback(func, 'requestAnimationFrame');
     RCTTiming.createTimer(id, 1, Date.now(), /* recurring */ false);
     return id;
   },
@@ -121,7 +120,7 @@ const JSTimers = {
       RCTTiming.setSendIdleEvents(true);
     }
 
-    const id = _allocateCallback(func, JSTimersExecution.Type.requestIdleCallback);
+    const id = _allocateCallback(func, 'requestIdleCallback');
     JSTimersExecution.requestIdleCallbacks.push(id);
     return id;
   },

Libraries/JavaScriptAppEngine/System/JSTimers/JSTimersExecution.js

@@ -14,7 +14,6 @@
 const Systrace = require('Systrace');
 
 const invariant = require('fbjs/lib/invariant');
-const keyMirror = require('fbjs/lib/keyMirror');
 const performanceNow = require('fbjs/lib/performanceNow');
 const warning = require('fbjs/lib/warning');
 
@@ -25,6 +24,13 @@ const IDLE_CALLBACK_FRAME_DEADLINE = 1;
 
 let hasEmittedTimeDriftWarning = false;
 
+export type JSTimerType =
+  'setTimeout' |
+  'setInterval' |
+  'requestAnimationFrame' |
+  'setImmediate' |
+  'requestIdleCallback';
+
 /**
  * JS implementation of timer functions. Must be completely driven by an
  * external clock signal, all that's stored here is timerID, timer type, and
@@ -32,18 +38,11 @@ let hasEmittedTimeDriftWarning = false;
  */
 const JSTimersExecution = {
   GUID: 1,
-  Type: keyMirror({
-    setTimeout: null,
-    setInterval: null,
-    requestAnimationFrame: null,
-    setImmediate: null,
-    requestIdleCallback: null,
-  }),
 
   // Parallel arrays
-  callbacks: [],
+  callbacks: ([] : Array<?Function>),
-  types: [],
+  types: ([] : Array<?JSTimerType>),
-  timerIDs: [],
+  timerIDs: ([] : Array<?number>),
   immediates: [],
   requestIdleCallbacks: [],
   identifiers: ([] : Array<null | {methodName: string}>),
@@ -85,21 +84,18 @@ const JSTimersExecution = {
     }
 
     // Clear the metadata
-    if (type === JSTimersExecution.Type.setTimeout ||
+    if (type === 'setTimeout' || type === 'setImmediate' ||
-        type === JSTimersExecution.Type.setImmediate ||
+        type === 'requestAnimationFrame' || type === 'requestIdleCallback') {
-        type === JSTimersExecution.Type.requestAnimationFrame ||
-        type === JSTimersExecution.Type.requestIdleCallback) {
       JSTimersExecution._clearIndex(timerIndex);
     }
 
     try {
-      if (type === JSTimersExecution.Type.setTimeout ||
+      if (type === 'setTimeout' || type === 'setInterval' ||
-          type === JSTimersExecution.Type.setInterval ||
+          type === 'setImmediate') {
-          type === JSTimersExecution.Type.setImmediate) {
         callback();
-      } else if (type === JSTimersExecution.Type.requestAnimationFrame) {
+      } else if (type === 'requestAnimationFrame') {
         callback(performanceNow());
-      } else if (type === JSTimersExecution.Type.requestIdleCallback) {
+      } else if (type === 'requestIdleCallback') {
         callback({
           timeRemaining: function() {
             // TODO: Optimisation: allow running for longer than one frame if