iOs build failing - UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'toLowerCase' of undefined

Question

Since yesterday, when I try to make a build for iOs it wont succeed and throw this error:

(node:3043) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'toLowerCase' of undefined
    at /Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/lib/list-emulator-build-targets:54:45
    at Array.forEach (<anonymous>)
    at /Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/lib/list-emulator-build-targets:52:44
    at Array.reduce (<anonymous>)
    at /Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/lib/list-emulator-build-targets:50:57
    at Array.reduce (<anonymous>)
    at /Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/lib/list-emulator-build-targets:45:28
    at _fulfilled (/Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/node_modules/q/q.js:854:54)
    at /Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/node_modules/q/q.js:883:30
    at Promise.promise.promiseDispatch (/Users/username/Documents/petpo-fe-mobile-bugs/platforms/ios/cordova/node_modules/q/q.js:816:13)
(node:3043) 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:3043) [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.

I've already tried cheking out a new project from git, removing and reinstalling modules, removing and readding the platform in ionic, I don't know what else I could try. Please, could someone give me some enlightenment on this issue?

Thanks in advance.

Answer 1

toLowerCase is used in plugins/cordova-plugin-ios-localized-strings/scripts/add_supported_languages.js?

If yes, there the value is undefined.

Please, try running: ionic build --prod

If you face an error -> There is a problem in your code.

If you face no error -> The problem happens when cordova is bundling your app.

If that last option, execute from bash (not cmd): ionic cordova build ios --prod or try removing and adding your platform again.

-Best regards.

Answer 2

I started having this issue too all of a sudden today. Removing and adding the platform did not do it for it. To resolve it, I removed the iOS platform version 4.5.5 and installed the latest version of the platform version which seems to fix it.

So do this:

1) Remove the iOS Platform:

ionic cordova platform remove ios

2) Install the latest version of iOS Platform:

ionic cordova platform add ios@latest --save

The above installed version 5.0.1 for me. After this, running the command ionic cordova build ios did not show any errors.