Add support for polyline borders

index.d.ts

@@ -211,6 +211,19 @@ declare module "react-native-maps-directions" {
      * Default: "#000"
      */
     strokeColor?: string;
+    /**
+     * @number
+     * The stroke border width to use for the path
+     * 0 indicates no border.
+     * Default: 0
+     */
+    strokeBorderWidth?: number;
+    /**
+    * @string
+    * The stroke border color to use for the path.
+    * Default: "#FFF"
+    */
+    strokeBorderColor?: string;
     /**
      * @Array
      * The stroke colors to use for the path (iOS only).

src/MapViewDirections.js

@@ -307,8 +307,19 @@ class MapViewDirections extends Component {
 			...props
 		} = this.props;
 
+		const borderPolylineProps = {
+			...props,
+			strokeWidth: props.strokeBorderWidth + props.strokeWidth,
+			strokeColor: props.strokeBorderColor,
+		};
+
 		return (
-			<Polyline coordinates={coordinates} {...props} />
+			<>
+				{props.strokeBorderWidth &&
+					<Polyline coordinates={coordinates} {...borderPolylineProps} />
+				}
+				<Polyline coordinates={coordinates} {...props} />
+			</>
 		);
 	}
 
@@ -352,6 +363,9 @@ MapViewDirections.propTypes = {
 	precision: PropTypes.oneOf(['high', 'low']),
 	timePrecision: PropTypes.oneOf(['now', 'none']),
 	channel: PropTypes.string,
+	strokeWidth: PropTypes.number,
+	strokeBorderWidth: PropTypes.number,
+	strokeBorderColor: PropTypes.string,
 };
 
 export default MapViewDirections;