build error with Angular 8.0.0 (TypeError: Cannot read property 'Promise' of undefined)

I updated my project to the latest Angular 8.0.0, @angular/fire 5.2.0-rc.1, firebase 6.1.0, firebaseui 4.0.0, firebaseui-angular 3.4.2.

ng serve works well. With ng build or ng build --prod, the build succeeds but I get a console error.

Uncaught TypeError: Cannot read property 'Promise' of undefined
    at da (npm.js:73)
    at npm.js:74
    at npm.js:425
    at Object../node_modules/firebaseui/dist/npm.js (npm.js:425)
    at __webpack_require__ (bootstrap:78)
    at Module../node_modules/firebaseui-angular/fesm2015/firebaseui-angular.js (firebaseui-angular.js:1)

Not sure where the issue is (haven’t yet tried to reproduce on a clean project). It might have to do with the Differential Loading introduced in Angular 8 (of the dialog polyfill). https://blog.angular.io/version-8-of-angular-smaller-bundles-cli-apis-and-alignment-with-the-ecosystem-af0261112a27

Update: Disabling differential loading (by setting "target": "es5" in tsconfig.json), resolves the error.

[PandiyanCool]

for me locally all works fine just on deploying to firebase hosting gives this error.

Same for me as well

However following workaround works.

If you switch target to “es5” in tsconfig.json (turns off differential loading), and run ng build again, the page loads fine.

[RaphaelJenni]

I created a beta version where the plugin is built with the angular 8 cli. PLease give it a try: npm install firebaseui-angular@4.0.0-beta.0