How to use the date-format.asString function in date-format

router.use(function(req, res, next) {
    count++;
    console.log('['+count+'] at: '+format.asString('hh:mm:ss.SSS', new Date())+' Url is: ' + req.url);
    next(); // make sure we go to the next routes and don't stop here
});

router.use(function(req, res, next) {
    count++;
    console.log('['+count+'] at: '+format.asString('hh:mm:ss.SSS', new Date())+' Url is: ' + req.url);
    next(); // make sure we go to the next routes and don't stop here
});

router.use(function(req, res, next) {
    count++;
    console.log('['+count+'] at: '+format.asString('hh:mm:ss.SSS', new Date())+' Url is: ' + req.url);
    next(); // make sure we go to the next routes and don't stop here
});

router.use(function(req, res, next) {
    count++;
    console.log('['+count+'] at: '+format.asString('hh:mm:ss.SSS', new Date())+' Url is: ' + req.url);
    next(); // make sure we go to the next routes and don't stop here
});

let format = dateFormat.ISO8601_FORMAT;
    if (specifier) {
      format = specifier;
      // Pick up special cases
      if (format === 'ISO8601') {
        format = dateFormat.ISO8601_FORMAT;
      } else if (format === 'ISO8601_WITH_TZ_OFFSET') {
        format = dateFormat.ISO8601_WITH_TZ_OFFSET_FORMAT;
      } else if (format === 'ABSOLUTE') {
        format = dateFormat.ABSOLUTETIME_FORMAT;
      } else if (format === 'DATE') {
        format = dateFormat.DATETIME_FORMAT;
      }
    }
    // Format the date
    return dateFormat.asString(format, loggingEvent.startTime);
  }

let format = dateFormat.ISO8601_FORMAT;
    if (specifier) {
      format = specifier;
      // Pick up special cases
      if (format === 'ISO8601') {
        format = dateFormat.ISO8601_FORMAT;
      } else if (format === 'ISO8601_WITH_TZ_OFFSET') {
        format = dateFormat.ISO8601_WITH_TZ_OFFSET_FORMAT;
      } else if (format === 'ABSOLUTE') {
        format = dateFormat.ABSOLUTETIME_FORMAT;
      } else if (format === 'DATE') {
        format = dateFormat.DATETIME_FORMAT;
      }
    }
    // Format the date
    return dateFormat.asString(format, loggingEvent.startTime);
  }

function writeExpense (expenseObjectParam) {
  var xdgBasedir = require('xdg-basedir');
  var expensesFilepath = xdgBasedir.data + '/wallet/expenses.csv';
  var fs = require('fs');
  var logSymbols = require('log-symbols');
  var prettyDate = require('date-format').asString('yyyy-MM-dd', new Date());

  var record = [
    prettyDate,
    expenseObjectParam.reason,
    expenseObjectParam.category,
    expenseObjectParam.credit,
    expenseObjectParam.debit
  ].join(delimiter);

  fs.appendFile(expensesFilepath, record + '\n', function (err) {
    if (err) {
      throw (err);
    } else {
      console.log('\n' + logSymbols.success + ' Expense written to file!' + '\n');
    }
  });

static format(date, format="yyyy-MM-dd hh:mm:ss") {
    if (!date) return "-";
    return DateFormat.asString(format, date);
  }

export const formatTime = (time,type) => {
  let zh = ["日", "一", "二", "三", "四", "五", "六"];
  let date = new Date(time * 1000);
  let oneWeekTime = 7 * 24 * 60 * 60 * 1000;
  let result = type === 'mm-dd' ? format.asString('MM-dd', date) :format.asString('yyyy-MM-dd hh:mm', date) + ' 星期' + zh[date.getDay()]
  return Date.now() - date>=oneWeekTime ?
    result
    :
    timeago().format(date)
}
export const getArticleInfo = detailArr => {

function startTime(loggingEvent) {
    return dateFormat.asString('hh:mm:ss', loggingEvent.startTime);
  }