code: function autoConvertAdd(a, b) {
    if (a !== null && b !== null) {
      // TODO(deboer): Support others.
      if (typeof a === 'string' && typeof b !== 'string') {
        return a + b.toString();
      }
  
      if (typeof a !== 'string' && typeof b === 'string') {
        return a.toString() + b;
      }
  
      return a + b;
    }
  
    if (a !== null) {
      return a;
    }
  
    if (b !== null) {
      return b;
    }
  
    return 0;
  }
docs: / Add the two arguments with automatic type conversion.