Neither dev serve or production build works. Angular.json set up according to your example with keep_classnames set to true.
Package.json:
{
"name": "mbnet",
"version": "0.0.0",
"license": "MIT",
"scripts": {
"ng": "ng",
"start": "ng serve --proxy-config proxy.config.json",
"build": "ng build",
"test": "ng test",
"lint": "ng lint",
"e2e": "ng e2e"
},
"readme": "removed dependencies: generator-code yo toastr",
"private": true,
"dependencies": {
"@angular/animations": "9.0.0-next.3",
"@angular/cdk": "^8.1.4",
"@angular/common": "9.0.0-next.3",
"@angular/compiler": "9.0.0-next.3",
"@angular/core": "9.0.0-next.3",
"@angular/forms": "9.0.0-next.3",
"@angular/material": "^8.1.4",
"@angular/platform-browser": "9.0.0-next.3",
"@angular/platform-browser-dynamic": "9.0.0-next.3",
"@angular/router": "9.0.0-next.3",
"@angular/service-worker": "9.0.0-next.3",
"classlist.js": "^1.1.20150312",
"core-js": "^3.1.4",
"oidc-client": "^1.9.0",
"rxjs": "6.5.2",
"tslib": "^1.10.0",
"zone.js": "^0.10.2"
},
"devDependencies": {
"@angular-devkit/build-angular": "0.803.0",
"@angular/cli": "^8.3.0",
"@angular/compiler-cli": "9.0.0-next.3",
"@angular/language-service": "^9.0.0-next.3",
"@types/jasmine": "^3.4.0",
"@types/jasminewd2": "~2.0.6",
"@types/node": "^12.7.2",
"angular-builder-custom-terser-options": "^1.0.1",
"codelyzer": "^5.1.0",
"jasmine-core": "~3.4.0",
"jasmine-spec-reporter": "~4.2.1",
"karma": "~4.2.0",
"karma-chrome-launcher": "^3.1.0",
"karma-cli": "~2.0.0",
"karma-coverage-istanbul-reporter": "^2.1.0",
"karma-jasmine": "^2.0.1",
"karma-jasmine-html-reporter": "^1.4.2",
"protractor": "^5.4.2",
"rxjs-tslint": "^0.1.7",
"ts-node": "^8.3.0",
"tslint": "^5.19.0",
"typescript": "3.5.3"
},
"browserslist": [
"> 0.5%",
"last 3 versions",
"not dead",
"IE 11"
]
}