chore: improve when to display warning

Author: erisu

lib/prepare.js

@@ -401,7 +401,10 @@ function updateProjectSplashScreen (platformConfig, locations) {
             break;
 
         case 'windowSplashScreenBrandingImage':
-            events.emit('warn', `"${themeKey}" is currently not supported by the splash screen compatibility library. https://issuetracker.google.com/issues/194301890`);
+            // display warning only when set.
+            if (cdvConfigPrefValue) {
+                events.emit('warn', `"${themeKey}" is currently not supported by the splash screen compatibility library. https://issuetracker.google.com/issues/194301890`);
+            }
 
             updateProjectSplashScreenImage(locations, themeKey, cdvConfigPrefKey, cdvConfigPrefValue);
 
@@ -547,7 +550,7 @@ function updateProjectSplashScreenImage (locations, themeKey, cdvConfigPrefKey,
         let emitType = 'verbose';
         let emmitMessage = `The "${cdvConfigPrefKey}" is undefined. Cordova's default will be used.`;
 
-        if (!fs.existsSync(cdvConfigPrefValue)) {
+        if (cdvConfigPrefValue && !fs.existsSync(cdvConfigPrefValue)) {
             emitType = 'warn';
             emmitMessage = `The "${cdvConfigPrefKey}" value does not exist. Cordova's default will be used.`;
         }