Flow-ify and cleanup JSTimers

Reviewed By: davidaurelio

Differential Revision: D3819511

fbshipit-source-id: 849133d013b026c3f95e988664f252bc35c65122

Libraries/JavaScriptAppEngine/System/JSTimers/JSTimers.js

@@ -7,116 +7,117 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule JSTimers
+ * @flow
  */
 'use strict';
 
 // Note that the module JSTimers is split into two in order to solve a cycle
 // in dependencies. NativeModules > BatchedBridge > MessageQueue > JSTimersExecution
-var RCTTiming = require('NativeModules').Timing;
+const RCTTiming = require('NativeModules').Timing;
-var JSTimersExecution = require('JSTimersExecution');
+const JSTimersExecution = require('JSTimersExecution');
+
+// Returns a free index if one is available, and the next consecutive index otherwise.
+function _getFreeIndex(): number {
+  let freeIndex = JSTimersExecution.timerIDs.indexOf(null);
+  if (freeIndex === -1) {
+    freeIndex = JSTimersExecution.timerIDs.length;
+  }
+  return freeIndex;
+}
+
+function _allocateCallback(func: Function, type: $Keys<typeof JSTimersExecution.Type>): number {
+  const id = JSTimersExecution.GUID++;
+  const freeIndex = _getFreeIndex();
+  JSTimersExecution.timerIDs[freeIndex] = id;
+  JSTimersExecution.callbacks[freeIndex] = func;
+  JSTimersExecution.types[freeIndex] = type;
+  return id;
+}
+
+function _freeCallback(timerID: number) {
+  // JSTimersExecution.timerIDs contains nulls after timers have been removed;
+  // ignore nulls upfront so indexOf doesn't find them
+  if (timerID == null) {
+    return;
+  }
+
+  const index = JSTimersExecution.timerIDs.indexOf(timerID);
+  // See corresponding comment in `callTimers` for reasoning behind this
+  if (index !== -1) {
+    JSTimersExecution._clearIndex(index);
+    const type = JSTimersExecution.types[index];
+    if (type !== JSTimersExecution.Type.setImmediate &&
+        type !== JSTimersExecution.Type.requestIdleCallback) {
+      RCTTiming.deleteTimer(timerID);
+    }
+  }
+}
 
 /**
  * JS implementation of timer functions. Must be completely driven by an
  * external clock signal, all that's stored here is timerID, timer type, and
  * callback.
  */
-var JSTimers = {
+const JSTimers = {
-  Types: JSTimersExecution.Types,
-
-  /**
-   * Returns a free index if one is available, and the next consecutive index
-   * otherwise.
-   */
-  _getFreeIndex: function() {
-    var freeIndex = JSTimersExecution.timerIDs.indexOf(null);
-    if (freeIndex === -1) {
-      freeIndex = JSTimersExecution.timerIDs.length;
-    }
-    return freeIndex;
-  },
-
   /**
    * @param {function} func Callback to be invoked after `duration` ms.
    * @param {number} duration Number of milliseconds.
    */
-  setTimeout: function(func, duration, ...args) {
+  setTimeout: function(func: Function, duration: number, ...args?: any): number {
-    var newID = JSTimersExecution.GUID++;
+    const id = _allocateCallback(() => func.apply(undefined, args),
-    var freeIndex = JSTimers._getFreeIndex();
+                                 JSTimersExecution.Type.setTimeout);
-    JSTimersExecution.timerIDs[freeIndex] = newID;
+    RCTTiming.createTimer(id, duration || 0, Date.now(), /* recurring */ false);
-    JSTimersExecution.callbacks[freeIndex] = function() {
+    return id;
-      return func.apply(undefined, args);
-    };
-    JSTimersExecution.types[freeIndex] = JSTimersExecution.Type.setTimeout;
-    RCTTiming.createTimer(newID, duration || 0, Date.now(), /** recurring */ false);
-    return newID;
   },
 
   /**
    * @param {function} func Callback to be invoked every `duration` ms.
    * @param {number} duration Number of milliseconds.
    */
-  setInterval: function(func, duration, ...args) {
+  setInterval: function(func: Function, duration: number, ...args?: any): number {
-    var newID = JSTimersExecution.GUID++;
+    const id = _allocateCallback(() => func.apply(undefined, args),
-    var freeIndex = JSTimers._getFreeIndex();
+                                 JSTimersExecution.Type.setInterval);
-    JSTimersExecution.timerIDs[freeIndex] = newID;
+    RCTTiming.createTimer(id, duration || 0, Date.now(), /* recurring */ true);
-    JSTimersExecution.callbacks[freeIndex] = function() {
+    return id;
-      return func.apply(undefined, args);
-    };
-    JSTimersExecution.types[freeIndex] = JSTimersExecution.Type.setInterval;
-    RCTTiming.createTimer(newID, duration || 0, Date.now(), /** recurring */ true);
-    return newID;
   },
 
   /**
    * @param {function} func Callback to be invoked before the end of the
    * current JavaScript execution loop.
    */
-  setImmediate: function(func, ...args) {
+  setImmediate: function(func: Function, ...args?: any) {
-    var newID = JSTimersExecution.GUID++;
+    const id = _allocateCallback(() => func.apply(undefined, args),
-    var freeIndex = JSTimers._getFreeIndex();
+                                 JSTimersExecution.Type.setImmediate);
-    JSTimersExecution.timerIDs[freeIndex] = newID;
+    JSTimersExecution.immediates.push(id);
-    JSTimersExecution.callbacks[freeIndex] = function() {
+    return id;
-      return func.apply(undefined, args);
-    };
-    JSTimersExecution.types[freeIndex] = JSTimersExecution.Type.setImmediate;
-    JSTimersExecution.immediates.push(newID);
-    return newID;
   },
 
   /**
    * @param {function} func Callback to be invoked every frame.
    */
-  requestAnimationFrame: function(func) {
+  requestAnimationFrame: function(func : Function) {
-    var newID = JSTimersExecution.GUID++;
+    const id = _allocateCallback(func, JSTimersExecution.Type.requestAnimationFrame);
-    var freeIndex = JSTimers._getFreeIndex();
+    RCTTiming.createTimer(id, 1, Date.now(), /* recurring */ false);
-    JSTimersExecution.timerIDs[freeIndex] = newID;
+    return id;
-    JSTimersExecution.callbacks[freeIndex] = func;
-    JSTimersExecution.types[freeIndex] = JSTimersExecution.Type.requestAnimationFrame;
-    RCTTiming.createTimer(newID, 1, Date.now(), /** recurring */ false);
-    return newID;
   },
 
   /**
    * @param {function} func Callback to be invoked every frame and provided
    * with time remaining in frame.
    */
-  requestIdleCallback: function(func) {
+  requestIdleCallback: function(func : Function) {
     if (JSTimersExecution.requestIdleCallbacks.length === 0) {
       RCTTiming.setSendIdleEvents(true);
     }
 
-    var newID = JSTimersExecution.GUID++;
+    const id = _allocateCallback(func, JSTimersExecution.Type.requestIdleCallback);
-    var freeIndex = JSTimers._getFreeIndex();
+    JSTimersExecution.requestIdleCallbacks.push(id);
-    JSTimersExecution.timerIDs[freeIndex] = newID;
+    return id;
-    JSTimersExecution.callbacks[freeIndex] = func;
-    JSTimersExecution.types[freeIndex] = JSTimersExecution.Type.requestIdleCallback;
-    JSTimersExecution.requestIdleCallbacks.push(newID);
-    return newID;
   },
 
-  cancelIdleCallback: function(timerID) {
+  cancelIdleCallback: function(timerID: number) {
-    JSTimers._clearTimerID(timerID);
+    _freeCallback(timerID);
-    var index = JSTimersExecution.requestIdleCallbacks.indexOf(timerID);
+    const index = JSTimersExecution.requestIdleCallbacks.indexOf(timerID);
     if (index !== -1) {
       JSTimersExecution.requestIdleCallbacks.splice(index, 1);
     }
@@ -126,43 +127,24 @@ var JSTimers = {
     }
   },
 
-  clearTimeout: function(timerID) {
+  clearTimeout: function(timerID: number) {
-    JSTimers._clearTimerID(timerID);
+    _freeCallback(timerID);
   },
 
-  clearInterval: function(timerID) {
+  clearInterval: function(timerID: number) {
-    JSTimers._clearTimerID(timerID);
+    _freeCallback(timerID);
   },
 
-  clearImmediate: function(timerID) {
+  clearImmediate: function(timerID: number) {
-    JSTimers._clearTimerID(timerID);
+    _freeCallback(timerID);
-    var index = JSTimersExecution.immediates.indexOf(timerID);
+    const index = JSTimersExecution.immediates.indexOf(timerID);
     if (index !== -1) {
       JSTimersExecution.immediates.splice(index, 1);
     }
   },
 
-  cancelAnimationFrame: function(timerID) {
+  cancelAnimationFrame: function(timerID: number) {
-    JSTimers._clearTimerID(timerID);
+    _freeCallback(timerID);
-  },
-
-  _clearTimerID: function(timerID) {
-    // JSTimersExecution.timerIDs contains nulls after timers have been removed;
-    // ignore nulls upfront so indexOf doesn't find them
-    if (timerID == null) {
-      return;
-    }
-
-    var index = JSTimersExecution.timerIDs.indexOf(timerID);
-    // See corresponding comment in `callTimers` for reasoning behind this
-    if (index !== -1) {
-      JSTimersExecution._clearIndex(index);
-      var type = JSTimersExecution.types[index];
-      if (type !== JSTimersExecution.Type.setImmediate &&
-          type !== JSTimersExecution.Type.requestIdleCallback) {
-        RCTTiming.deleteTimer(timerID);
-      }
-    }
   },
 };
 

Libraries/JavaScriptAppEngine/System/JSTimers/JSTimersExecution.js

@@ -7,6 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *
  * @providesModule JSTimersExecution
+ * @flow
  */
 'use strict';
 
@@ -39,35 +40,43 @@ const JSTimersExecution = {
     requestIdleCallback: null,
   }),
 
-  // Parallel arrays:
+  // Parallel arrays
   callbacks: [],
   types: [],
   timerIDs: [],
   immediates: [],
   requestIdleCallbacks: [],
 
+  errors: (null : ?[Error]),
+
   /**
    * Calls the callback associated with the ID. Also unregister that callback
    * if it was a one time timer (setTimeout), and not unregister it if it was
    * recurring (setInterval).
    */
-  callTimer(timerID, frameTime) {
+  callTimer(timerID: number, frameTime: number) {
     warning(
       timerID <= JSTimersExecution.GUID,
       'Tried to call timer with ID %s but no such timer exists.',
       timerID
     );
-    const timerIndex = JSTimersExecution.timerIDs.indexOf(timerID);
+
     // timerIndex of -1 means that no timer with that ID exists. There are
     // two situations when this happens, when a garbage timer ID was given
     // and when a previously existing timer was deleted before this callback
     // fired. In both cases we want to ignore the timer id, but in the former
     // case we warn as well.
+    const timerIndex = JSTimersExecution.timerIDs.indexOf(timerID);
     if (timerIndex === -1) {
       return;
     }
+
     const type = JSTimersExecution.types[timerIndex];
     const callback = JSTimersExecution.callbacks[timerIndex];
+    if (!callback || !type) {
+      console.error('No callback found for timerID ' + timerID);
+      return;
+    }
 
     // Clear the metadata
     if (type === JSTimersExecution.Type.setTimeout ||
@@ -83,8 +92,7 @@ const JSTimersExecution = {
           type === JSTimersExecution.Type.setImmediate) {
         callback();
       } else if (type === JSTimersExecution.Type.requestAnimationFrame) {
-        const currentTime = performanceNow();
+        callback(performanceNow());
-        callback(currentTime);
       } else if (type === JSTimersExecution.Type.requestIdleCallback) {
         callback({
           timeRemaining: function() {
@@ -96,12 +104,14 @@ const JSTimersExecution = {
         });
       } else {
         console.error('Tried to call a callback with invalid type: ' + type);
-        return;
       }
     } catch (e) {
-      // Don't rethrow so that we can run every other timer.
+      // Don't rethrow so that we can run all timers.
-      JSTimersExecution.errors = JSTimersExecution.errors || [];
+      if (!JSTimersExecution.errors) {
-      JSTimersExecution.errors.push(e);
+        JSTimersExecution.errors = [e];
+      } else {
+        JSTimersExecution.errors.push(e);
+      }
     }
   },
 
@@ -109,14 +119,16 @@ const JSTimersExecution = {
    * This is called from the native side. We are passed an array of timerIDs,
    * and
    */
-  callTimers(timerIDs) {
+  callTimers(timerIDs: [number]) {
     invariant(
       timerIDs.length !== 0,
       'Cannot call `callTimers` with an empty list of IDs.'
     );
 
     JSTimersExecution.errors = null;
-    timerIDs.forEach((id) => { JSTimersExecution.callTimer(id); });
+    for (let i = 0; i < timerIDs.length; i++) {
+      JSTimersExecution.callTimer(timerIDs[i], 0);
+    }
 
     const errors = JSTimersExecution.errors;
     if (errors) {
@@ -135,15 +147,12 @@ const JSTimersExecution = {
     }
   },
 
-  callIdleCallbacks: function(frameTime) {
+  callIdleCallbacks: function(frameTime: number) {
-    const { Timing } = require('NativeModules');
-
     if (FRAME_DURATION - (performanceNow() - frameTime) < IDLE_CALLBACK_FRAME_DEADLINE) {
       return;
     }
 
     JSTimersExecution.errors = null;
-
     if (JSTimersExecution.requestIdleCallbacks.length > 0) {
       const passIdleCallbacks = JSTimersExecution.requestIdleCallbacks.slice();
       JSTimersExecution.requestIdleCallbacks = [];
@@ -154,6 +163,7 @@ const JSTimersExecution = {
     }
 
     if (JSTimersExecution.requestIdleCallbacks.length === 0) {
+      const { Timing } = require('NativeModules');
       Timing.setSendIdleEvents(false);
     }
 
@@ -180,7 +190,7 @@ const JSTimersExecution = {
       // Use for loop rather than forEach as per @vjeux's advice
       // https://github.com/facebook/react-native/commit/c8fd9f7588ad02d2293cac7224715f4af7b0f352#commitcomment-14570051
       for (let i = 0; i < passImmediates.length; ++i) {
-        JSTimersExecution.callTimer(passImmediates[i]);
+        JSTimersExecution.callTimer(passImmediates[i], 0);
       }
     }
 
@@ -206,7 +216,7 @@ const JSTimersExecution = {
   /**
    * Called from native (in development) when environment times are out-of-sync.
    */
-  emitTimeDriftWarning(warningMessage) {
+  emitTimeDriftWarning(warningMessage: string) {
     if (hasEmittedTimeDriftWarning) {
       return;
     }
@@ -214,7 +224,7 @@ const JSTimersExecution = {
     console.warn(warningMessage);
   },
 
-  _clearIndex(i) {
+  _clearIndex(i: number) {
     JSTimersExecution.timerIDs[i] = null;
     JSTimersExecution.callbacks[i] = null;
     JSTimersExecution.types[i] = null;