Unhandled error detected in the injected client.js script.

[Babar-Bashir]

You can disable this script in webdev by passing --no-injected-client if it
is preventing your app from loading, but note that this will also prevent
all debugging and hot reload/restart functionality from working.

The original error is below, please file an issue at
https://github.com/dart-lang/webdev/issues/new and attach this output:

TypeError: null: type 'JSNull' is not a subtype of type 'String'

at Object.wrapException (http://localhost:1214/dwds/src/injected/client.js:1249:43)
at Object._asString (http://localhost:1214/dwds/src/injected/client.js:2840:15)
at main__closure7.call$1 (http://localhost:1214/dwds/src/injected/client.js:26677:54)
at _EventStreamSubscription_closure.call$1 (http://localhost:1214/dwds/src/injected/client.js:26040:26)
at StaticClosure._rootRunUnary (http://localhost:1214/dwds/src/injected/client.js:4382:16)
at _CustomZone.runUnary$2$2 (http://localhost:1214/dwds/src/injected/client.js:14273:39)
at _CustomZone.runUnaryGuarded$1$2 (http://localhost:1214/dwds/src/injected/client.js:14220:14)
at _CustomZone_bindUnaryCallbackGuarded_closure.call$1 (http://localhost:1214/dwds/src/injected/client.js:14407:25)
at _callDartFunctionFast1 (http://localhost:1214/dwds/src/injected/client.js:7680:25)
at http://localhost:1214/dwds/src/injected/client.js:7656:18