Current 15 version breaks compatibility with Firefox 60 (included in browserslist) and optimization true

[argentum388]

Which @angular/* package(s) are the source of the bug?

compiler-cli, compiler

Is this a regression?

Yes

Description

Despite of including old Firefox browser versions (60-78) to browserslist application bundle throws an error in browser console

"SyntaxError: expected expression, got '?'[Learn More] vendor.js"

Note! This bug is only reproduced with optimization.scripts: true in configuration

It seems optimization procedures add to bundle Logical nullish assignment operator "?? "which Firefox 60-78 don't support

Please provide a link to a minimal reproduction of the bug

No response

Please provide the exception or error you saw

SyntaxError: expected expression, got '?'[Learn More]  vendor.js

Please provide the environment you discovered this bug in (run ng version)

Angular CLI: 15.0.1
Node: 14.20.1
Package Manager: npm 6.14.17
OS: linux x64

Angular: 15.0.1
... animations, cli, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router

Package                         Version
---------------------------------------------------------
@angular-devkit/architect       0.1500.1
@angular-devkit/build-angular   15.0.1
@angular-devkit/core            15.0.1
@angular-devkit/schematics      15.0.1
@angular/cdk                    15.0.0
@angular/material               15.0.0
@schematics/angular             15.0.1
rxjs                            7.5.7
typescript                      4.8.4

Anything else?

.browserslistrc

Firefox > 59

[alan-agius4]

Officially Firefox 60 is not supported by Angular,
See: https://angular.io/guide/browser-support#browser-support for a list of supported browsers.

However there might be something going on here. To look into this further we'd require a minimal reproduction.

You can read here why this is needed. A good way to make a minimal repro is to create a new app via ng new repro-app and adding the minimum possible code to show the problem. Then you can push this repository to github and link it here.

This might be related to your directory structure so its really important to get an accurate repro to diagnose this.

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