title: Extra character is gettting added in API URL in angular
body: <p>Environment file</p>
  <pre><code>export const environment = {
      production: false,
      name: 'local',
      apiUrl: 'https://dev.xyz.com/v1',
  };
  </code></pre>
  <p>API service</p>
  <pre><code>login(input: ILogin): Observable&lt;any&gt; {
      Common.showConsoleLog('demoAPIReq', input);
      const url1 = 'https://dev.xyz.com/v1/auth/login'
      const url = `${environment.apiUrl}${consts.LOGIN}`;
      return this.http.post(url, input, { 
          headers: Common.authHeader(), observe: 'response'
      }).pipe(tap (data =&gt; Common.showConsoleLog('demoAPIRes', data)),
      catchError(this.handleError('login'))
  );
  </code></pre>
  <p>Common file</p>
  <pre><code>static authHeader(): any {
      const httpBearerOptions = {
          headers: new HttpHeaders({
              'Content-Type': 'application/json',
          }),
      };
      return httpBearerOptions.headers;
  }
  </code></pre>
  <p>Const file</p>
  <pre><code>export const consts = {
      ROUTE_HOME: 'home',
      ROUTE_LOGIN: 'login',
      ROUTE_REGISTER: 'register',
      ROUTE_DASHBOARD: 'dashboard',
      LOGIN: '​/auth/login',
  };
  </code></pre>
  <p>If I pass url1 in post api then its working fine , Also <code>const url3 = environment.apiUrl + '/auth/login';</code> is also working  but I concate string as in <code>const url = `${environment.apiUrl}${consts.LOGIN}`;</code>
  then its add some weird extra character in url when I checked into network tab as like below <a href="https://i.stack.imgur.com/xd9kJ.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/xd9kJ.png" alt="enter image description here" /></a></p>