Mocha记者展示Moment.js对象

Question

使用Mocha，Chai和Moment.js假定以下简化的测试用例：

describe( 'test', () => {
  it( 'should not show that many details', async () => {

    const res = { d:  null };

    Assert.equal( res, { d:  Moment( '2018-12-03' ) });

  });
});

目前，这产生了非常详尽的报告，显示了Moment.js实例的所有内部结构。

1) test
   should not show that many details:

  AssertionError [ERR_ASSERTION]: { d: null } == { d: moment("2018-12-03T00:00:00.000") }
  + expected - actual

   {
  -  "d": [null]
  +  "d": {
  +    "_d": [Date: 2018-12-02T23:00:00.000Z]
  +    "_f": "YYYY-MM-DD"
  +    "_i": "2018-12-03"
  +    "_isAMomentObject": true
  +    "_isUTC": false
  +    "_isValid": true
  +    "_locale": {
  +      "_abbr": "en"
  +      "_calendar": {
  +        "lastDay": "[Yesterday at] LT"
  +        "lastWeek": "[Last] dddd [at] LT"
  +        "nextDay": "[Tomorrow at] LT"
  +        "nextWeek": "dddd [at] LT"
  +        "sameDay": "[Today at] LT"
  +        "sameElse": "L"
  +      }
  +      "_config": {
  +        "abbr": "en"
  +        "calendar": {
  +          "lastDay": "[Yesterday at] LT"
  +          "lastWeek": "[Last] dddd [at] LT"
  +          "nextDay": "[Tomorrow at] LT"
  +          "nextWeek": "dddd [at] LT"
  +          "sameDay": "[Today at] LT"
  +          "sameElse": "L"
  +        }
  +        "dayOfMonthOrdinalParse": /\d{1,2}(th|st|nd|rd)/
  +        "invalidDate": "Invalid date"
  +        "longDateFormat": {
  +          "L": "MM/DD/YYYY"
  +          "LL": "MMMM D, YYYY"
  +          "LLL": "MMMM D, YYYY h:mm A"
  +          "LLLL": "dddd, MMMM D, YYYY h:mm A"
  +          "LT": "h:mm A"
  +          "LTS": "h:mm:ss A"
  +        }
  +        "meridiemParse": /[ap]\.?m?\.?/i
  +        "months": [
  +          "January"
  +          "February"
  +          "March"
  +          "April"
  +          "May"
  +          "June"
  +          "July"
  +          "August"
  +          "September"
  +          "October"
  +          "November"
  +          "December"
  +        ]
  +        "monthsShort": [
  +          "Jan"
  +          "Feb"
  +          "Mar"
  +          "Apr"
  +          "May"
  +          "Jun"
  +          "Jul"
  +          "Aug"
  +          "Sep"
  +          "Oct"
  +          "Nov"
  +          "Dec"
  +        ]
  +        "ordinal": [Function]
  +        "relativeTime": {
  +          "M": "a month"
  +          "MM": "%d months"
  +          "d": "a day"
  +          "dd": "%d days"
  +          "future": "in %s"
  +          "h": "an hour"
  +          "hh": "%d hours"
  +          "m": "a minute"
  +          "mm": "%d minutes"
  +          "past": "%s ago"
  +          "s": "a few seconds"
  +          "ss": "%d seconds"
  +          "y": "a year"
  +          "yy": "%d years"
  +        }
  +        "week": {
  +          "dow": 0
  +          "doy": 6
  +        }
  +        "weekdays": [
  +          "Sunday"
  +          "Monday"
  +          "Tuesday"
  +          "Wednesday"
  +          "Thursday"
  +          "Friday"
  +          "Saturday"
  +        ]
  +        "weekdaysMin": [
  +          "Su"
  +          "Mo"
  +          "Tu"
  +          "We"
  +          "Th"
  +          "Fr"
  +          "Sa"
  +        ]
  +        "weekdaysShort": [
  +          "Sun"
  +          "Mon"
  +          "Tue"
  +          "Wed"
  +          "Thu"
  +          "Fri"
  +          "Sat"
  +        ]
  +      }
  +      "_dayOfMonthOrdinalParse": /\d{1,2}(th|st|nd|rd)/
  +      "_dayOfMonthOrdinalParseLenient": /\d{1,2}(th|st|nd|rd)|\d{1,2}/
  +      "_invalidDate": "Invalid date"
  +      "_longDateFormat": {
  +        "L": "MM/DD/YYYY"
  +        "LL": "MMMM D, YYYY"
  +        "LLL": "MMMM D, YYYY h:mm A"
  +        "LLLL": "dddd, MMMM D, YYYY h:mm A"
  +        "LT": "h:mm A"
  +        "LTS": "h:mm:ss A"
  +      }
  +      "_meridiemParse": /[ap]\.?m?\.?/i
  +      "_months": [
  +        "January"
  +        "February"
  +        "March"
  +        "April"
  +        "May"
  +        "June"
  +        "July"
  +        "August"
  +        "September"
  +        "October"
  +        "November"
  +        "December"
  +      ]
  +      "_monthsShort": [
  +        "Jan"
  +        "Feb"
  +        "Mar"
  +        "Apr"
  +        "May"
  +        "Jun"
  +        "Jul"
  +        "Aug"
  +        "Sep"
  +        "Oct"
  +        "Nov"
  +        "Dec"
  +      ]
  +      "_relativeTime": {
  +        "M": "a month"
  +        "MM": "%d months"
  +        "d": "a day"
  +        "dd": "%d days"
  +        "future": "in %s"
  +        "h": "an hour"
  +        "hh": "%d hours"
  +        "m": "a minute"
  +        "mm": "%d minutes"
  +        "past": "%s ago"
  +        "s": "a few seconds"
  +        "ss": "%d seconds"
  +        "y": "a year"
  +        "yy": "%d years"
  +      }
  +      "_week": {
  +        "dow": 0
  +        "doy": 6
  +      }
  +      "_weekdays": [
  +        "Sunday"
  +        "Monday"
  +        "Tuesday"
  +        "Wednesday"
  +        "Thursday"
  +        "Friday"
  +        "Saturday"
  +      ]
  +      "_weekdaysMin": [
  +        "Su"
  +        "Mo"
  +        "Tu"
  +        "We"
  +        "Th"
  +        "Fr"
  +        "Sa"
  +      ]
  +      "_weekdaysShort": [
  +        "Sun"
  +        "Mon"
  +        "Tue"
  +        "Wed"
  +        "Thu"
  +        "Fri"
  +        "Sat"
  +      ]
  +      "ordinal": [Function]
  +    }
  +    "_pf": {
  +      "charsLeftOver": 0
  +      "empty": false
  +      "invalidFormat": false
  +      "invalidMonth": [null]
  +      "iso": true
  +      "meridiem": [undefined]
  +      "nullInput": false
  +      "overflow": -1
  +      "parsedDateParts": [
  +        2018
  +        11
  +        3
  +      ]
  +      "rfc2822": false
  +      "unusedInput": []
  +      "unusedTokens": []
  +      "userInvalidated": false
  +      "weekdayMismatch": false
  +    }
  +  }
   }

如何将输出缩短为.toString()或类似名称提供的内容？

我本来以为有某种我可以覆盖的序列化函数，但是到目前为止还不能。