When I add IOS platform on ionic project getting error "UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'indexOf' of null"

ionic cordova platform add ios --save
> cordova platform add ios --save
Using cordova-fetch for cordova-ios@^4.5.4

Adding ios project...

Creating Cordova project for the iOS platform:

Path: platforms\ios
Package: io.yin.tablesits
Name: tablesits
iOS project created with cordova-ios@4.5.4

(node:13560) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'indexOf' of null
at parseWhitelistUrlForATS (D:\test\ts\platforms\ios\cordova\lib\prepare.js:1038:27)
at D:\test\ts\platforms\ios\cordova\lib\prepare.js:965:23
at Array.reduce ()
at processAccessAndAllowNavigationEntries (D:\test\ts\platforms\ios\cordova\lib\prepare.js:956:10)
at writeATSEntries (D:\test\ts\platforms\ios\cordova\lib\prepare.js:1081:16)
at updateProject (D:\test\ts\platforms\ios\cordova\lib\prepare.js:217:15)
at D:\test\ts\platforms\ios\cordova\lib\prepare.js:59:20
at _fulfilled (D:\test\ts\platforms\ios\cordova\node_modules\q\q.js:854:54)
at self.promiseDispatch.done (D:\test\ts\platforms\ios\cordova\node_modules\q\q.js:883:30)
at Promise.promise.promiseDispatch (D:\test\ts\platforms\ios\cordova\node_modules\q\q.js:816:13)
(node:13560) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:13560) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

-----------------------------
$ ionic info

cli packages: (C:\Users\DELL\AppData\Roaming\npm\node_modules)

@ionic/cli-utils : 1.19.2
ionic (Ionic CLI) : 3.20.0

global packages:

cordova (Cordova CLI) : 8.0.0

local packages:

@ionic/app-scripts : 3.1.8
Cordova Platforms : android 7.0.0 ios 4.5.4
Ionic Framework : ionic-angular 3.9.2

System:

Android SDK Tools : 26.1.1
Node : v9.8.0
npm : 5.8.0
OS : Windows 10

Environment Variables:

ANDROID_HOME : C:\Users\DELL\AppData\Local\Android\Sdk

Misc:

backend : pro