target: es2020 doesn't work with ?. null conditional operator

[vivainio]

🐞 bug report

Affected Package

@angular/cli

Is this a regression?

No

Description

?. operator doesn't work if you set target: "ES2020" in tsconfig.base.json

🔬 Minimal Reproduction

Check out https://github.com/vivainio/repro-angular-es2020-fail

run "ng build" and observe the compiler error.

If you change it back to "target": "es2016", ng build succeeds.

🔥 Exception or Error

ERROR in ./src/app/app.component.ts 38:20
Module parse failed: Unexpected token (38:20)
File was processed with these loaders:
 * ./node_modules/@ngtools/webpack/src/index.js
You may need an additional loader to handle the result of these loaders.
|         this.title = 'test2020';
|         const a = undefined;
>         const b = a?.name;
|     }
| }

🌍 Your Environment

Angular Version:

Angular CLI: 10.0.1
Node: 12.18.1
OS: win32 x64

Angular: 10.0.3
... animations, common, compiler, compiler-cli, core, forms
... platform-browser, platform-browser-dynamic, router
Ivy Workspace: Yes

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.1000.1
@angular-devkit/build-angular     0.1000.1
@angular-devkit/build-optimizer   0.1000.1
@angular-devkit/build-webpack     0.1000.1
@angular-devkit/core              10.0.1
@angular-devkit/schematics        10.0.1
@angular/cli                      10.0.1
@ngtools/webpack                  10.0.1
@schematics/angular               10.0.1
@schematics/update                0.1000.1
rxjs                              6.5.5
typescript                        3.9.6
webpack                           4.43.0

Anything else relevant?

I'm aware that native async/await is not supported by Zone.js, but for the purposes of this discussions I don't care about this gap.

[JoostK]

This is not currently supported in Webpack, see webpack/webpack#10227

[JoostK]

Transferred to the CLI repo, however this is not actionable for the CLI at the moment.

[vivainio]

As instructed in webpack/webpack#10227, changing "target" to "es2019" is a functional workaround

[alan-agius4]

Let’s continue tracking this issue as part of: #17555

Since this will only be fixed in Webpack 5.

[angular-automatic-lock-bot]

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