Remove dead code from animation classes

src/Animated.js

@@ -10,9 +10,7 @@ import createAnimatedComponent from './createAnimatedComponent';
 import decay from './animations/decay';
 import timing from './animations/timing';
 import spring from './animations/spring';
-import TimingAnimation from './animations/TimingAnimation';
-import SpringAnimation from './animations/SpringAnimation';
-import DecayAnimation from './animations/DecayAnimation';
+import Animation from './animations/Animation';
 import {
   addWhitelistedNativeProps,
   addWhitelistedUIProps,
@@ -26,10 +24,18 @@ import {
 import SpringUtils from './animations/SpringUtils';
 import useValue from './useValue';
 
-
-const decayWrapper = backwardCompatibleAnimWrapper(decay, DecayAnimation);
-const timingWrapper = backwardCompatibleAnimWrapper(timing, TimingAnimation);
-const springWrapper = backwardCompatibleAnimWrapper(spring, SpringAnimation);
+const decayWrapper = backwardCompatibleAnimWrapper(
+  decay,
+  Animation.decayDefaultState
+);
+const timingWrapper = backwardCompatibleAnimWrapper(
+  timing,
+  Animation.timingDefaultState
+);
+const springWrapper = backwardCompatibleAnimWrapper(
+  spring,
+  Animation.springDefaultState
+);
 const Animated = {
   // components
   View: createAnimatedComponent(View),
@@ -72,19 +78,16 @@ export {
   Easing,
   Transitioning,
   Transition,
-  createTransitioningComponent, 
-
+  createTransitioningComponent,
   // classes
   AnimatedClock as Clock,
   AnimatedValue as Value,
   AnimatedNode as Node,
-
   // animations
   decayWrapper as decay,
   timingWrapper as timing,
   springWrapper as spring,
   SpringUtils,
-
   // hooks
   useValue,
 };

src/animations/Animation.js

@@ -1,9 +1,32 @@
-// Important note: start() and stop() will only be called at most once.
-// Once an animation has been stopped or finished its course, it will
-// not be reused.
+import AnimatedValue from '../core/InternalAnimatedValue';
+
 class Animation {
-  start(fromValue, onUpdate, onEnd, previousAnimation, animatedValue) {}
-  stop() {}
+  static springDefaultState() {
+    return {
+      position: new AnimatedValue(0),
+      finished: new AnimatedValue(0),
+      velocity: new AnimatedValue(0),
+      time: new AnimatedValue(0),
+    };
+  }
+
+  static decayDefaultState() {
+    return {
+      position: new AnimatedValue(0),
+      finished: new AnimatedValue(0),
+      velocity: new AnimatedValue(0),
+      time: new AnimatedValue(0),
+    };
+  }
+
+  static timingDefaultState() {
+    return {
+      position: new AnimatedValue(0),
+      finished: new AnimatedValue(0),
+      time: new AnimatedValue(0),
+      frameTime: new AnimatedValue(0),
+    };
+  }
 }
 
 export default Animation;

src/animations/backwardCompatibleAnimWrapper.js

@@ -11,9 +11,9 @@ import {
 import Clock from '../core/AnimatedClock';
 import { evaluateOnce } from '../derived/evaluateOnce';
 
-function createOldAnimationObject(node, AnimationClass, value, config) {
+function createOldAnimationObject(node, animationStateDefaults, value, config) {
   const newClock = new Clock();
-  const currentState = AnimationClass.getDefaultState();
+  const currentState = animationStateDefaults();
   let alwaysNode;
   let isStarted = false;
   let isDone = false;
@@ -104,11 +104,14 @@ function createOldAnimationObject(node, AnimationClass, value, config) {
  * Depending on the arguments list we either return animation node or return an
  * animation object that is compatible with the original Animated API
  */
-export default function backwardsCompatibleAnimWrapper(node, AnimationClass) {
+export default function backwardsCompatibleAnimWrapper(
+  node,
+  animationStateDefaults
+) {
   return (clock, state, config) => {
     if (config !== undefined) {
       return node(clock, state, config);
     }
-    return createOldAnimationObject(node, AnimationClass, clock, state);
+    return createOldAnimationObject(node, animationStateDefaults, clock, state);
   };
 }