code: @Nonnull
    public JSVar var (@Nonnull @Nonempty final String sName,
                      @Nullable final String sInitValue) throws JSNameAlreadyExistsException
    {
      return var (sName, sInitValue == null ? JSExpr.NULL : JSExpr.lit (sInitValue));
    }
docs: Adds a local variable declaration to this block
  
  @param sName
  Name of the variable
  @param sInitValue
  Initialization value for this variable.
  @return Newly generated {@link JSVar}
  @throws JSNameAlreadyExistsException
  if the name is not unique