Q:

Error encountered in metadata generated for exported symbol when constructing an angular 6 library

I'm getting the following error while performing 'ng build' from my library. 
I'm using Angular 6 at the moment, but I believe this error is not version related. 

/home/rafaelvicio/desenv/my-lib/arquitetura-web/projects/pf-siseg/src/lib/keycloak-service/keycloak.service.ts:13:1:
  Error encountered in metadata generated for exported symbol
  'KeycloakService':
  /home/rafaelvicio/desenv/my-lib/arquitetura-web/projects/pf-siseg/src/lib/keycloak-service/keycloak.service.ts:18:12:
  Metadata collected contains an error that will be reported at runtime:
  Only initialized variables and constants can be referenced because the
  value of this variable is needed by the template compiler. 
  {"__symbolic":"error","message":"Variable not
  initialized","line":17,"character":11} Error:
  /home/rafaelvicio/desenv/my-lib/arquitetura-web/projects/pf-siseg/src/lib/keycloak-service/keycloak.service.ts:13:1:
  Error encountered in metadata generated for exported symbol
  'KeycloakService':
  /home/rafaelvicio/desenv/my-lib/arquitetura-web/projects/pf-siseg/src/lib/keycloak-service/keycloak.service.ts:18:12:
  Metadata collected contains an error that will be reported at runtime:
  Only initialized variables and constants can be referenced because the
  value of this variable is needed by the template compiler. 
  {"__symbolic":"error","message":"Variable not
  initialized","line":17,"character":11}
      at /home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/metadata/collector.js:707:31
      at Array.forEach ()
      at validateMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/metadata/collector.js:695:46)
      at MetadataCollector.getMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/metadata/collector.js:550:21)
      at MetadataCache.getMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/transformers/metadata_cache.js:86:41)
      at Object.getSourceFileMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/transformers/compiler_host.js:112:56)
      at Object.readMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/transformers/metadata_reader.js:46:37)
      at TsCompilerAotCompilerTypeCheckHostAdapter.getMetadataFor (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler-cli/src/transformers/compiler_host.js:464:38)
      at StaticSymbolResolver.getModuleMetadata (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler/src/aot/static_symbol_resolver.js:480:49)
      at StaticSymbolResolver._createSymbolsOf (/home/rafaelvicio/desenv/my-lib/arquitetura-web/node_modules/@angular/compiler/src/aot/static_symbol_resolver.js:268:33)

keycloak.service.ts:
import { Injectable } from '@angular/core';
import { KeycloakLoginOptions } from './keycloak.d';

import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';

import * as Keycloak from './keycloak';

export type KeycloakClient = Keycloak. KeycloakInstance;
type InitOptions = Keycloak. KeycloakInitOptions;

@Injectable()
export class KeycloakService {

    constructor(private http: HttpClient) { }

    static keycloakAuth: KeycloakClient;

.... More code here

A:

add // @dynamic before the class that declares static methods

