StringBuffer equivalent in typescript

Question

I am trying to convert a Dart pipe to typescript, but there does not seem to be an equivalent of StringBuffer in typescript. The Dart code is shown below

.dart

@Pipe( name: 'titleCase' )
class TitleCasePipe extends PipeTransform {
  dynamic transform( String value, List args ) {
    StringBuffer buffer = new StringBuffer( );

    if ( !isNull( value ) ) {
      List<String> list = value.split( '' );

      if ( value.startsWith( new RegExp( r"^[is]{1,2}([A-Z]|[0-9])" ) ) ) {
        int start = 2;
        List<String> sublist = list.sublist( start );
        return sublist.join( '' );
      }

      for ( int i = 0; i < list.length; i++ ) {
        if ( i == 0 ) {
          buffer.write( list[i].toUpperCase( ) );
          continue;
        }

        if ( isUppercase( list[i] ) ) {
          buffer.write( ' ' );
          buffer.write( list[i] );
          continue;
        }

        buffer.write( list[i] );
      }
    }
    return buffer.toString( );
  }
}

What is the best substitution for String buffer or how best can I convert the pipe using typescript.

Thanks

Answer 1

I would use an array

@Pipe({ name: 'titleCase'})
class TitleCasePipe extends PipeTransform {
  transform(value:string, args:any[] ):any {
    buffer:string[] = [];

    if ( !isNull( value ) ) {
      list:string[] = value.split( '' );


      if ( value.match(/^[is]{1,2}([A-Z]|[0-9]).*/ ) ) {
        start:number = 2;
        sublist:string[] = list.slice( start );
        return sublist.join( '' );
      }

      for (i = 0; i < list.length; i++ ) {
        if ( i == 0 ) {
          buffer.push( list[i].toUpperCase( ) );
          continue;
        }

        if ( isUppercase( list[i] ) ) {
          buffer.push( ' ' );
          buffer.push( list[i] );
          continue;
        }

        buffer.push( list[i] );
      }
    }
    return buffer.join('');
  }
}

(caution - not tested)