diff --git a/flow-typed/npm/viewport-mercator-project_vx.x.x.js b/flow-typed/npm/viewport-mercator-project_vx.x.x.js
index 66db3d8e9..f4d06997b 100644
--- a/flow-typed/npm/viewport-mercator-project_vx.x.x.js
+++ b/flow-typed/npm/viewport-mercator-project_vx.x.x.js
@@ -11,26 +11,43 @@ type Viewport = {
   bearing: number
 };
 
+type FlyToInterpolatorOpts = {
+  curve?: number,
+  speed?: number,
+  screenSpeed?: number,
+  maxDuraiton?: number
+};
+
 declare module 'viewport-mercator-project' {
   declare export class WebMercatorViewport {
-    constructor(Viewport) : WebMercatorViewport;
+    constructor(Viewport): WebMercatorViewport;
 
-    width: number,
-    height: number,
-    longitude: number,
-    latitude: number,
-    zoom: number,
-    pitch: number,
-    bearing: number,
+    width: number;
+    height: number;
+    longitude: number;
+    latitude: number;
+    zoom: number;
+    pitch: number;
+    bearing: number;
 
     project(xyz: Array<number>): Array<number>;
     unproject(xyz: Array<number>): Array<number>;
     getMapCenterByLngLatPosition({lngLat: Array<number>, pos: Array<number>}): Array<number>;
-    fitBounds(bounds: [[Number,Number],[Number,Number]], options: any): WebMercatorViewport;
+    fitBounds(bounds: [[Number, Number], [Number, Number]], options: any): WebMercatorViewport;
   }
 
-  declare export function normalizeViewportProps(props: Viewport) : Viewport;
-  declare export function flyToViewport(startProps: Viewport, endProps: Viewport, t: number) : Viewport;
+  declare export function normalizeViewportProps(props: Viewport): Viewport;
+  declare export function flyToViewport(
+    startProps: Viewport,
+    endProps: Viewport,
+    t: number,
+    opts?: FlyToInterpolatorOpts
+  ): Viewport;
+  declare export function getFlyToDuration(
+    startProps: Viewport,
+    endProps: Viewport,
+    opts?: FlyToInterpolatorOpts
+  ): number;
 
   declare export default typeof WebMercatorViewport;
 }
diff --git a/package.json b/package.json
index b7abbe262..cf32168b9 100644
--- a/package.json
+++ b/package.json
@@ -39,6 +39,7 @@
     "publish-prod": "ocular-publish prod",
     "publish-beta": "ocular-publish beta",
     "test": "flow check && ocular-test",
+    "test-only": "ocular-test",
     "test-fast": "flow check && ocular-test fast",
     "metrics": "ocular-metrics",
     "update-release-branch": "scripts/update-release-branch.sh"
@@ -49,7 +50,7 @@
     "mjolnir.js": "^2.2.0",
     "prop-types": "^15.7.2",
     "react-virtualized-auto-sizer": "^1.0.2",
-    "viewport-mercator-project": "^6.1.0"
+    "viewport-mercator-project": "^6.3.0-alpha.0"
   },
   "devDependencies": {
     "@babel/plugin-proposal-class-properties": "^7.4.4",
diff --git a/src/utils/transition/transition-interpolator.js b/src/utils/transition/transition-interpolator.js
index 53ebd1797..117928e6a 100644
--- a/src/utils/transition/transition-interpolator.js
+++ b/src/utils/transition/transition-interpolator.js
@@ -1,6 +1,7 @@
 // @flow
 import {equals} from '../math-utils';
 import assert from '../assert';
+import type {MapStateProps} from '../map-state';
 
 export default class TransitionInterpolator {
   propNames: Array<string> = [];
diff --git a/yarn.lock b/yarn.lock
index 4ab15e2eb..c443063fd 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -9392,10 +9392,10 @@ verror@1.10.0:
     core-util-is "1.0.2"
     extsprintf "^1.2.0"
 
-viewport-mercator-project@^6.1.0:
-  version "6.1.1"
-  resolved "https://registry.yarnpkg.com/viewport-mercator-project/-/viewport-mercator-project-6.1.1.tgz#d7b2cb3cb772b819f1daab17cf4019102a9102a6"
-  integrity sha512-nI0GEmXnESwZxWSJuaQkdCnvOv6yckUfqqFbNB8KWVbQY3eUExVM4ZziqCVVs5mNznLjDF1auj6HLW5D5DKcng==
+viewport-mercator-project@^6.3.0-alpha.0:
+  version "6.3.0-alpha.0"
+  resolved "https://registry.yarnpkg.com/viewport-mercator-project/-/viewport-mercator-project-6.3.0-alpha.0.tgz#d72e4dcfc281870a80afaf356327db48e52898f0"
+  integrity sha512-ZMaJC0wt12/j9LHE9WFCVvwxJ8xK9iklGHCwHiwZZ52iwwMoEQW9QeSpi/dx5PfrfekaCFn4lkpQtEamLqNSBQ==
   dependencies:
     "@babel/runtime" "^7.0.0"
     gl-matrix "^3.0.0"