title: NestJS throw from ExceptionFilter
body: <p>I try to use an <code>ExceptionFilter</code> to map exceptions to their HTTP counterpart.</p>
  
  <p>This is my code : </p>
  
  <pre><code>@Catch(EntityNotFoundError)
  export class EntityNotFoundFilter implements ExceptionFilter {
      catch(exception: EntityNotFoundError, _host: ArgumentsHost) {
          throw new NotFoundException(exception.message);
      }
  }
  </code></pre>
  
  <p>But, when the filter code is executed, I got a <code>UnhandledPromiseRejectionWarning</code></p>
  
  <pre><code> (node:3065) UnhandledPromiseRejectionWarning: Error: [object Object]
      at EntityNotFoundFilter.catch ([...]/errors.ts:32:15)
      at ExceptionsHandler.invokeCustomFilters ([...]/node_modules/@nestjs/core/exceptions/exceptions-handler.js:49:26)
       at ExceptionsHandler.next ([...]/node_modules/@nestjs/core/exceptions/exceptions-handler.js:13:18)
       at [...]/node_modules/@nestjs/core/router/router-proxy.js:12:35
       at &lt;anonymous&gt;
       at process._tickCallback (internal/process/next_tick.js:182:7)
   (node:3065) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 5)
  </code></pre>
  
  <p>How can I fix this ? </p>