Rename TrackablePointer.elapsedTime to TrackablePointer.duration

demos/pointer-demo/demo.js

         ctx.fillText('x: ' + pointer.position.x.toFixed(5), position.x, position.y + 2 * TEXT_LINE_HEIGHT);
         ctx.fillText('y: ' + pointer.position.y.toFixed(5), position.x, position.y + 3 * TEXT_LINE_HEIGHT);
         ctx.fillText('speed: ' + pointer.velocity.length().toFixed(5), position.x, position.y + 4 * TEXT_LINE_HEIGHT);
-        ctx.fillText('time: ' + pointer.elapsedTime.toFixed(5), position.x, position.y + 5 * TEXT_LINE_HEIGHT);
+        ctx.fillText('time: ' + pointer.duration.toFixed(5), position.x, position.y + 5 * TEXT_LINE_HEIGHT);
     }
 }
 

docs/api/trackable-pointer.md

 
 The current velocity of the pointer, given in space units per second. You can get the current speed of motion by calculating the [magnitude](vector2.md#length) of this vector.
 
-### elapsedTime
+### duration
 
-`pointer.elapsedTime: number, read-only`
+`pointer.duration: number, read-only`
 
 The elapsed time, in seconds, since the tracking of this pointer began.
 
 
 `pointer.totalDistance: number, read-only`
 
-How much this pointer has moved, in space units, since its tracking began. You can get the average speed of motion by calculating the ratio `totalDistance / elapsedTime`.
+How much this pointer has moved, in space units, since its tracking began. You can get the average speed of motion by calculating the ratio `totalDistance / duration`.
 
 ### isPrimary
 

src/trackers/pointer-tracker/pointer-tracker.ts

             const velocity = deltaPosition._clone()._scale(inverseDeltaTime);
 
             // determine the elapsed time since the tracking began
-            const elapsedTime = previous ? previous.elapsedTime + deltaTime : 0;
+            const duration = previous ? previous.duration + deltaTime : 0;
 
             // determine how much this pointer has moved since its tracking began
             const totalDistance = previous ? previous.totalDistance + deltaPosition.length() : 0;
 
             // we create new trackable instances on each frame;
             // these will be exported and consumed by the user
-            this._newPointers.set(id, { id, phase, position, deltaPosition, initialPosition, velocity, elapsedTime, totalDistance, isPrimary, kind });
+            this._newPointers.set(id, { id, phase, position, deltaPosition, initialPosition, velocity, duration, totalDistance, isPrimary, kind });
 
         }
 
     {
         this._activePointers.forEach((trackable, id) => {
             if(trackable.phase == 'stationary') {
-                (trackable as any).elapsedTime += deltaTime;
+                (trackable as any).duration += deltaTime;
                 /*
                 this._activePointers.set(id, Object.assign({}, trackable, {
-                    elapsedTime: trackable.elapsedTime + deltaTime
+                    duration: trackable.duration + deltaTime
                 }));
                 */
             }

src/trackers/pointer-tracker/trackable-pointer.ts

     readonly velocity: Vector2;
 
     /** elapsed time, in seconds, since the tracking of this pointer began */
-    readonly elapsedTime: number;
+    readonly duration: number;
 
     /** how much this pointer has moved, in space units, since its tracking began */
     readonly totalDistance: number;