title: DatePipe.transform show InvalidPipeArgument for 'dd-MM-yyyy'
body: <p>Recently Angular DatePipe is showing an InvalidPipeArgument error but the String date seams to be correct.
  Can any one see some error?  this is my code using <strong>Typescript</strong> and <strong>Angular 6</strong></p>
  
  <pre><code>let datePipe: DatePipe = new DatePipe("es-ES");
  let dia_sele: string = "";
                  try {
                    let fecha_formateada = this.datePipe.transform('23-01-2019', 'dd-MM-yyyy','es-ES');
                    dia_sele = fecha_formateada;
                  } catch (e) {
                    dia_sele = "";
                    console.log( "-&gt;err:" + e);
                  }
  </code></pre>
  
  <p>And this is the error showing in console from Chrome Windows:      </p>
  
  <pre><code>core.js:14597 ERROR Error: Uncaught (in promise): Error: InvalidPipeArgument: 'Unable to convert "23-01-2019" into a date' for pipe 'DatePipe'
  Error: InvalidPipeArgument: 'Unable to convert "23-01-2019" into a date' for pipe 'DatePipe'
      at invalidPipeArgumentError (common.js:4013)
      at DatePipe.transform
  </code></pre>