dayjs(item).isValid() is not validate item.values

[admin00001]

Describe the bug
in moment:

const o = {values: ['2017-06-17']}
moment(o).isValid() === true

but in dayjs

const o = {values: ['2017-06-17']}
dayjs(o).isValid() === false

Expected behavior
I hope that when an Object has property of values , you should cover it.

like this

const o = {values: ['2017-06-17']}
dayjs(o).isValid === dayjs(o.values).isValid() === true

Information

• Day.js Version [e.g. v1.10.2]
• OS: window
• Browser : chrome 91.0.4472.106
• Time zone: [e.g. GMT-07:00 DST (Pacific Daylight Time)]

[imwh0im]

My guess, is that this is due to the different handling for invalid values.
look that here. 👇

const o = {values: ['2017-06-17']};

moment(o); // Moment<2021-06-21T00:00:00+09:00>
moment(o).format('YYYY-MM-DD'); // 2021-06-21

dayjs(o); // M {
// '$L': 'en',
// '$d': Invalid Date,
// '$x': {},
// '$y': NaN,
// '$M': NaN,
// '$D': NaN,
// '$W': NaN,
// '$H': NaN,
// '$m': NaN,
// '$s': NaN,
// '$ms': NaN
// }
dayjs(o).format('YYYY-MM-DD'); // Invalid Date

Please give feedback if my comment it's wrong.

[admin00001]

I am not sure that you aleady understand my point; what i say is dayjs(o).isValid() , not dayjs(o).format('YYYY-MM-DD') ;

[imwh0im]

used format() it was for understand.

An important point is moment(o) and dayjs(o) values.

moment(o) it was return "now". (my timezone is Korea)
but dayjs(o) return "Invalid Date".

"moment" and "dayjs" is returned unintentional values.

i guess it was means parameter o is not suppported.
so commented to you.

You may not understand the explanation.. because of My English is not good enough. 😢
but i Hope this helps

[BePo65]

Looking at the documentation of moment object parsing you see that moment requires an object with properties like 'year' or 'month' to parse it to a date.

What @imwh0im was trying to explain is that the result from moment is valid, because in the case of an object with invalid properties moment simply takes the current date and that of course is valid (not sure, if this is what you had in mind when checking for dayjs(o).isValid() === true)

In dayjs you have to use the objectSupport plugin; using this, you get the same result as with moment.

var objectSupport = require("dayjs/plugin/objectSupport");
dayjs.extend(objectSupport);

const o = { year: 2017, month: 6, day: 17 }
resultDayjs = dayjs(o)
resultDayjs.isValid() === true
resultDayjs.format('DD-MM-YYYY')  // '17-07-2017'