Attribute noModule is ignored by Safari 10

[Embraser01]

🐞 bug report

Affected Package

The issue is caused by the use of the `nomodule` attribute in the `<script>` tag.

Is this a regression?

Yes, it was working in Angular 7

Description

The build generated by Angular v8 with both es5 and es2015 flavor cannot be loaded on Safari 10. It's caused by the fact that Safari doesn't seems to acknownledge the nomodule attribute and so, load both versions which leads to an error:

Zone.js has detected that ZoneAwarePromise `(window|global).Promise` has been overwritten. Most likely cause is that a Promise polyfill has been loaded after Zone.js (Polyfilling Promise api is not necessary when zone.js is loaded. If you must load one, do so before loading zone.js.)

🔬 Minimal Reproduction

You can see a simple (no config) repo here and here, the same site deployed.

🔥 Exception or Error

You can see in the console

Zone.js has detected that ZoneAwarePromise `(window|global).Promise` has been overwritten. Most likely cause is that a Promise polyfill has been loaded after Zone.js (Polyfilling Promise api is not necessary when zone.js is loaded. If you must load one, do so before loading zone.js.)

🌍 Your Environment

Angular Version: v8.0.0

     _                      _                 ____ _     ___
    / \   _ __   __ _ _   _| | __ _ _ __     / ___| |   |_ _|
   / △ \ | '_ \ / _` | | | | |/ _` | '__|   | |   | |    | |
  / ___ \| | | | (_| | |_| | | (_| | |      | |___| |___ | |
 /_/   \_\_| |_|\__, |\__,_|_|\__,_|_|       \____|_____|___|
                |___/
    

Angular CLI: 8.0.1
Node: 10.15.0
OS: win32 x64
Angular: 8.0.0
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.800.1
@angular-devkit/build-angular     0.800.1
@angular-devkit/build-optimizer   0.800.1
@angular-devkit/build-webpack     0.800.1
@angular-devkit/core              8.0.1
@angular-devkit/schematics        8.0.1
@angular/cli                      8.0.1
@ngtools/webpack                  8.0.1
@schematics/angular               8.0.1
@schematics/update                0.800.1
rxjs                              6.4.0
typescript                        3.4.5
webpack                           4.30.0

Anything else relevant?

It seems to be related to Safari ignoring nomodule attribute.
It affect at least Safari 10.0.0 (on iOS 10.3).
I'll test on more devices but it takes some time (I test on simulator).

I also found this

[Embraser01]

Actually, there is already the polyfill to fix this inside polyfill-es2015 but doesn't seems to work... (maybe it's loaded after es5 version?)

https://caniuse.com/#feat=es6-module

[trotyl]

Technically speaking, Safari 10 isn't on the support list, current stable version is 12 so that officially supported versions are 11 and 12.