Invalid Date parsing a time without a date

[lsorin77]

Something like dayjs('4:43', 'h:mm') is returning an Invalid Date. If you add in a date, e.g. dayjs('12-25-1995 4:43', 'MM-DD-YYYY h:mm'), then it works. I need to be able to parse just the time, without a date, which is what I am currently doing with momentjs. I am using Typescript/Angular, dayjs version 1.10.5. extending customParseFormat plugin, which is probably inferred from it working with the date.

[imwh0im]

Tried this issue.

  const input = '4:30';
  const format = 'h:mm';

  const result = dayjs(input, format);
  const result_1 = moment(input, format);

  console.log(result.format('YYYY-MM-DD HH:mm:ss'));  // 2021-06-29 04:30:00
  console.log(result_1.format('YYYY-MM-DD HH:mm:ss'));  // 2021-06-29 04:30:00

But in my case it was same result in "momentjs" and "dayjs".
Can you explain the issue in more detail?

[lsorin77]

console.log("dayjs 4:43", dayjs('4:43', 'h:mm').toDate());
returns an Invalid Date

console.log("moment 4:43", moment('4:43', 'h:mm').toDate());
returns "2021-06-29T09:43:00.000Z"

Another example/use case for parsing just the time portion to validate the time input is valid:
const parsed = dayjs(
value,
['h:mm A', 'h:mm:ss A', 'h:mm:ss.SSSSSSSSS A', 'HH:mm:ss.SSSSSSS', 'HH:mm:ss', 'HH:mm'],
true,
);
console.log(parsed.isValid()); // false

    const parsed = moment(
        value,
        ['h:mm A', 'h:mm:ss A', 'h:mm:ss.SSSSSSSSS A', 'HH:mm:ss.SSSSSSS', 'HH:mm:ss', 'HH:mm'],
        true,
    );
    console.log(parsed.isValid()); // true

[imwh0im]

In my case.

import dayjs from 'dayjs';
import customParseFormat from 'dayjs/plugin/customParseFormat';

dayjs.extend(customParseFormat);  // try this.

console.log(dayjs('4:43', 'h:mm').toDate());  // 2021-06-29T19:43:00.000Z

Add plugin customParseFormat and extend it.

[lsorin77]

That is exactly what I'm doing, except my import is
import customParseFormat from 'dayjs';
Angular version 11

[imwh0im]

Not

import customParseFormat from "dayjs";

Should be

import customParseFormat from "dayjs/plugin/customParseFormat";

Try it.
If has some problems or already tried it. uninstall "dayjs" and reinstall that.
I hope this will helps

[lsorin77]

Thanks, that fixed the time parsing, but now I am having an issue with parsing the following datetime string:
dayjs('2021-06-30T16:55+00:00', 'YYYY-MM-DD[T]HH:mmZ', true)
This returns an Invalid Date but works in moment
It appears to work if I remove the strict=true parameter.
I found the following open issue -- #929. Is this related to that?

[imwh0im]

i guess same issue.