RegExp in NgModule annotation throws 'Expression form not supported'

[mtraynham]

🐞 Bug report

Command (mark with an x)

- [ ] new
- [X] build
- [ ] serve
- [ ] test
- [ ] e2e
- [ ] generate
- [ ] add
- [ ] update
- [ ] lint
- [ ] xi18n
- [ ] run
- [ ] config
- [ ] help
- [ ] version
- [ ] doc

Is this a regression?

Not sure. According to the documentation of the library I'm using, I think they assume it's always worked.

Description

I'm using [angulartics2](https://github.com/angulartics/angulartics2), which provides integrations with 3rd party analytics such as Google Analytics. One of the features of this library is watching and reporting route changes. There is a configuration option to clean up `id` references in routes, documentation is [here](https://github.com/angulartics/angulartics2#remove-ids-from-url-paths).

My configuration for this module is as follows:

    Angulartics2Module.forRoot({
      pageTracking: {
        clearIds: true,
        idsRegExp: /^[a-zA-Z]+-[0-9a-zA-Z_-]{22}$/
      }
    })

When building for production (ng build --prod) and using a RegExp (non-constructor variant), it gives me this exception.

Date: 2019-02-18T20:42:19.190Z
Hash: f87abc34a327d3cd4386
Time: 5030ms
chunk {0} runtime.a5dd35324ddfd942bef1.js (runtime) 1.41 kB [entry] [rendered]
chunk {1} es2015-polyfills.67c5cff8371af1f9a1d4.js (es2015-polyfills) 56.4 kB [initial] [rendered]
chunk {2} main.cde404c57fbcc43faae1.js (main) 128 bytes [initial] [rendered]
chunk {3} polyfills.70c2c870c3a0f5c90635.js (polyfills) 130 bytes [initial] [rendered]
chunk {4} styles.3ff695c00d717f2d2a11.css (styles) 0 bytes [initial] [rendered]

ERROR in app/app.module.ts(18,20): Error during template compile of 'AppModule'
  Expression form not supported.

Alternatively, when using the constructor format,

    Angulartics2Module.forRoot({
      pageTracking: {
        clearIds: true,
        idsRegExp: new RegExp('^[a-zA-Z]+-[0-9a-zA-Z_-]{22}$')
      }
    })

The above actually compiles and builds the distribution, but if you look at the distributed JS, it has removed that particular line and the output JS looks like:

r.qb(256,H,{settings:{pageTracking:{clearIds:!0}}}

🔬 Minimal Reproduction

ng new test
cd test
npm install --save angulartics2

Import and add the following to the main AppModule

import {Angulartics2Module} from 'angulartics2';
...
    Angulartics2Module.forRoot({
      pageTracking: {
        clearIds: true,
        idsRegExp: /^[a-zA-Z]+-[0-9a-zA-Z_-]{22}$/  // Throws exception
        // idsRegExp: new RegExp('^[a-zA-Z]+-[0-9a-zA-Z_-]{22}$') // Not compiled to output
      }
    })

Then run ng build --prod. The error is:

ERROR in app/app.module.ts(18,20): Error during template compile of 'AppModule'
  Expression form not supported.

Use the other variant and check the dist/foobar/main.xxxxxxx.js file. Do a find for clearIds. Notice no key in that same dict is defined for idsRegExp.

🔥 Exception or Error

ERROR in app/app.module.ts(18,20): Error during template compile of 'AppModule'
  Expression form not supported.

🌍 Your Environment

Angular CLI: 7.3.2
Node: 11.9.0
OS: darwin x64
Angular: 7.2.5
... animations, common, compiler, compiler-cli, core, forms
... language-service, platform-browser, platform-browser-dynamic
... router

Package                           Version
-----------------------------------------------------------
@angular-devkit/architect         0.13.2
@angular-devkit/build-angular     0.13.2
@angular-devkit/build-optimizer   0.13.2
@angular-devkit/build-webpack     0.13.2
@angular-devkit/core              7.3.2
@angular-devkit/schematics        7.3.2
@angular/cli                      7.3.2
@ngtools/webpack                  7.3.2
@schematics/angular               7.3.2
@schematics/update                0.13.2
rxjs                              6.3.3
typescript                        3.2.4
webpack                           4.29.0

Anything else relevant?
Mac OSX 10.14.3

[alan-agius4]

Thanks for reporting this however regexp don’t seem to be supported as expression syntax.

https://angular.io/guide/aot-compiler#expression-syntax

[mtraynham]

@alan-agius4 If new is supported then, why does new RegExp('^[a-zA-Z]+-[0-9a-zA-Z_-]{22}$') get completely removed from the AOT compiled output? I looked in the dist directory and can find 0 references to it.

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