clean code before merge

Author: ShanMa1991

CHANGELOG.md

@@ -26,7 +26,7 @@
 * Renamed public property `MBCongestionAttribute` to `CongestionAttribute`. ([#2808](https://github.com/mapbox/mapbox-navigation-ios/pull/2808))
 * `NavigationViewController.mapView` was renamed to `NavigationViewController.navigationMapView`. ([#2808](https://github.com/mapbox/mapbox-navigation-ios/pull/2808))
 * `NavigationMapView.highlightBuildings(at:in3D:)` was renamed to `NavigationMapView.highlightBuildings(at:in3D:completion:)`. ([#2827](https://github.com/mapbox/mapbox-navigation-ios/pull/2827))
-* Add ability to show congestion levels with different colors on alternative route lines, after receiving multiple routes in `RouteResponse`  if  `NavigationMapView.showsAlternativeCongestion`  is set to  `true`. ([#2887](https://github.com/mapbox/mapbox-navigation-ios/pull/2887))
+* Add ability to show congestion levels with different colors on alternative route lines, after receiving multiple routes in `RouteResponse` if `NavigationMapView.showsCongestionForAlternativeRoutes` is set to `true`. ([#2887](https://github.com/mapbox/mapbox-navigation-ios/pull/2887))
 
 ### Location tracking
 

Example/ViewController.swift

@@ -58,7 +58,7 @@ class ViewController: UIViewController {
 
             startButton.isEnabled = true
             // Show congestion levels on alternative route lines if there're multiple routes in the response.
-            navigationMapView.showsAlternativeCongestion = true
+            navigationMapView.showsCongestionForAlternativeRoutes = true
             navigationMapView.show(routes)
             navigationMapView.showWaypoints(on: currentRoute)
         }

Sources/MapboxNavigation/NavigationMapView+VanishingRouteLine.swift

@@ -344,32 +344,17 @@ extension NavigationMapView {
      Given a congestion level, return its associated color.
      */
     func congestionColor(for congestionLevel: String?, isMain: Bool) -> UIColor {
-        if isMain {
-            switch congestionLevel {
-            case "low":
-                return trafficLowColor
-            case "moderate":
-                return trafficModerateColor
-            case "heavy":
-                return trafficHeavyColor
-            case "severe":
-                return trafficSevereColor
-            default:
-                return trafficUnknownColor
-            }
-        } else {
-            switch congestionLevel {
-            case "low":
-                return alternativeTrafficLowColor
-            case "moderate":
-                return alternativeTrafficModerateColor
-            case "heavy":
-                return alternativeTrafficHeavyColor
-            case "severe":
-                return alternativeTrafficSevereColor
-            default:
-                return alternativeTrafficUnknownColor
-            }
+        switch congestionLevel {
+        case "low":
+            return isMain ? trafficLowColor : alternativeTrafficLowColor
+        case "moderate":
+            return isMain ? trafficModerateColor : alternativeTrafficModerateColor
+        case "heavy":
+            return isMain ? trafficHeavyColor : alternativeTrafficHeavyColor
+        case "severe":
+            return isMain ? trafficSevereColor : alternativeTrafficSevereColor
+        default:
+            return isMain ? trafficUnknownColor : alternativeTrafficUnknownColor
         }
     }
 

Sources/MapboxNavigation/NavigationMapView.swift

@@ -58,9 +58,9 @@ open class NavigationMapView: UIView {
     /**
      Controls whether to show congestion levels on alternative route lines. Defaults to `false`.
 
-     If `true` and there're multiple routes to choose, the alternative route lines would display the congestion levels at different colors, similar to the main route. To customize the congestion colors that represent different congestion levels, override the `alternativeTrafficUnknownColor` , `alternativeTrafficLowColor`, `alternativeTrafficModerateColor`, `alternativeTrafficHeavyColor`, `alternativeTrafficSevereColor` property for the `NavigationMapView.appearance()`.
+     If `true` and there're multiple routes to choose, the alternative route lines would display the congestion levels at different colors, similar to the main route. To customize the congestion colors that represent different congestion levels, override the `alternativeTrafficUnknownColor`, `alternativeTrafficLowColor`, `alternativeTrafficModerateColor`, `alternativeTrafficHeavyColor`, `alternativeTrafficSevereColor` property for the `NavigationMapView.appearance()`.
      */
-    public var showsAlternativeCongestion: Bool = false
+    public var showsCongestionForAlternativeRoutes: Bool = false
 
     enum IdentifierType: Int {
         case source
@@ -647,10 +647,8 @@ open class NavigationMapView: UIView {
         lineLayer.layout?.lineJoin = .constant(.round)
         lineLayer.layout?.lineCap = .constant(.round)
 
-        if showsAlternativeCongestion {
-            if let gradientStops = routeLineGradient(route, fractionTraveled: 0.0, isMain: false) {
-                lineLayer.paint?.lineGradient = .expression((Expression.routeLineGradientExpression(gradientStops)))
-            }
+        if showsCongestionForAlternativeRoutes, let gradientStops = routeLineGradient(route, fractionTraveled: 0.0, isMain: false) {
+            lineLayer.paint?.lineGradient = .expression((Expression.routeLineGradientExpression(gradientStops)))
         }
         mapView.style.addLayer(layer: lineLayer, layerPosition: LayerPosition(below: parentLayerIndentifier))