title: Angular - Display negative value in parentheses and maintain 'type: number'
body: <p>I am working with a chart of percentages, and I want to format the negative numbers to be in parentheses instead of with a negative sign. I can find how to do this with a pipe... but ONLY if I have the currency pipe that then transforms the number type to a string. Is there a way to keep the type a number AND substitute parentheses for the negative sign? Here is the pipe:</p>
  
  <pre><code>export class MinusToParensPipe implements PipeTransform {
      transform(value: any, args?: any): any {
          return value.charAt(0) === '-' ?
              '(' + value.substring(1, value.length) + ')' :
              value;
      }
  }
  </code></pre>