code: function parsePostfixExpression() {
          var expr = parseLeftHandSideExpressionAllowCall(), token;
  
          token = lookahead();
          if (token.type !== Token.Punctuator) {
              return expr;
          }
  
          if ((match('++') || match('--')) && !peekLineTerminator()) {
              // 11.3.1, 11.3.2
              if (strict && expr.type === Syntax.Identifier && isRestrictedWord(expr.name)) {
                  throwErrorTolerant({}, Messages.StrictLHSPostfix);
              }
  
              if (!isLeftHandSide(expr)) {
                  throwError({}, Messages.InvalidLHSInAssignment);
              }
  
              expr = {
                  type: Syntax.UpdateExpression,
                  operator: lex().value,
                  argument: expr,
                  prefix: false
              };
          }
  
          return expr;
      }
docs: 11.3 Postfix Expressions