diff --git a/example/src/demos/raws/allShapes.raw b/example/src/demos/raws/allShapes.raw
index 58cde99..f8fa745 100644
--- a/example/src/demos/raws/allShapes.raw
+++ b/example/src/demos/raws/allShapes.raw
@@ -23,7 +23,9 @@ interface Route {
 // tslint:disable-next-line:no-var-requires
 const route: Route = require('./route.json');
 
-const mappedRoute = route.points.map(point => [point.lat, point.lng]);
+const mappedRoute = route.points.map(
+  point => [point.lat, point.lng] as [number, number]
+);
 
 const Map = ReactMapboxGl({ accessToken: token });
 
@@ -52,7 +54,7 @@ const multiPolygonPaint = {
 };
 
 export interface State {
-  center: number[];
+  center: [number, number];
   circleRadius: number;
   routeIndex: number;
   zoom: [number];
diff --git a/example/src/demos/raws/geojsonLayer.raw b/example/src/demos/raws/geojsonLayer.raw
index ba5ccfd..064b0cd 100644
--- a/example/src/demos/raws/geojsonLayer.raw
+++ b/example/src/demos/raws/geojsonLayer.raw
@@ -34,7 +34,7 @@ export interface Props {
 }
 
 class GeoJsonLayer extends React.Component<Props> {
-  private center = [-77.01239, 38.91275];
+  private center = [-77.01239, 38.91275] as [number, number];
 
   // tslint:disable-next-line:no-any
   private onClickCircle = (evt: any) => {
diff --git a/example/src/demos/raws/heatmap.raw b/example/src/demos/raws/heatmap.raw
index 6c97aa6..46683fe 100644
--- a/example/src/demos/raws/heatmap.raw
+++ b/example/src/demos/raws/heatmap.raw
@@ -55,7 +55,7 @@ const layerPaint = {
 };
 
 export default class Heatmap extends React.Component<Props> {
-  private center = [-0.109970527, 51.52916347];
+  private center = [-0.109970527, 51.52916347] as [number, number];
 
   // tslint:disable-next-line:no-any
   private onStyleLoad = (map: any) => {
diff --git a/example/src/demos/raws/htmlFeatures.raw b/example/src/demos/raws/htmlFeatures.raw
index 92c52ba..19d2efd 100644
--- a/example/src/demos/raws/htmlFeatures.raw
+++ b/example/src/demos/raws/htmlFeatures.raw
@@ -34,14 +34,14 @@ const mapStyle = {
 export interface Place {
   id: string;
   name: string;
-  center: number[];
+  center: [number, number];
 }
 
 export interface State {
   query: string;
   options: Place[];
   selected?: Place;
-  center: number[];
+  center: [number, number];
 }
 
 const req = (url: string, body?: any, method = 'GET') =>
diff --git a/example/src/demos/raws/londonCycle.raw b/example/src/demos/raws/londonCycle.raw
index 6368288..ca97f6b 100644
--- a/example/src/demos/raws/londonCycle.raw
+++ b/example/src/demos/raws/londonCycle.raw
@@ -35,8 +35,8 @@ const StyledPopup = styled.div`
 `;
 
 export interface State {
-  fitBounds?: number[][];
-  center: number[];
+  fitBounds?: [[number, number], [number, number]];
+  center: [number, number];
   zoom: [number];
   station?: Station;
   stations: StationDict;
diff --git a/example/src/demos/raws/switchStyle.raw b/example/src/demos/raws/switchStyle.raw
index b5058d5..697b198 100644
--- a/example/src/demos/raws/switchStyle.raw
+++ b/example/src/demos/raws/switchStyle.raw
@@ -81,7 +81,7 @@ const switchStyles = Object.keys(styles).filter(k =>
 export interface State {
   styleKey: string;
   featuresPostion: number[][];
-  mapCenter: number[];
+  mapCenter: [number, number];
   renderLayer: boolean;
 }
 
@@ -90,7 +90,7 @@ export interface Props {
   onStyleLoad?: (map: any) => any;
 }
 
-const InitialUserPostion = [-0.2416815, 51.5285582];
+const InitialUserPostion = [-0.2416815, 51.5285582] as [number, number];
 
 class StyleUpdate extends React.Component<Props, State> {
   public state: State = {
diff --git a/example/src/demos/raws/threeDMap.raw b/example/src/demos/raws/threeDMap.raw
index 21f8c91..b254e4e 100644
--- a/example/src/demos/raws/threeDMap.raw
+++ b/example/src/demos/raws/threeDMap.raw
@@ -28,11 +28,11 @@ export interface Props {
   onStyleLoad?: (map: any) => any;
 }
 
-class ThreeDMap extends React.Component<Props, {}> {
+class ThreeDMap extends React.Component<Props> {
   private zoom: [number] = [15];
   private bearing: [number] = [-60];
   private pitch: [number] = [60];
-  private center = [-0.0824952, 51.5144951];
+  private center = [-0.0824952, 51.5144951] as [number, number];
 
   // tslint:disable-next-line:no-any
   private onStyleLoad = (map: any) => {