format throws when used on "Invalid Date" with advancedformat + timezone + utc

[SamuelPoulin]

Describe the bug
When using the following format string on dayjs(null) the resulting date is "Invalid Date"

lll

When using the following string, dayjs throws

lll z

Thrown error:

Unhandled Runtime Error

RangeError: date value is not finite in DateTimeFormat.formatToParts()

dayjs(null).format('lll z')
           ^

Expected behavior
dayjs should display "Invalid Date" and not throw an error

Information

• Day.js Version v1.10.5
• OS: Windows
• Browser Firefox 89.0.2 (64-bit)
• Time zone: EST

[imwh0im]

In typescript?

[imwh0im]

In Javascript

var dayjs = require("dayjs");

console.log(dayjs(null).format('lll z'));  // Invalid Date

In Typescript

import dayjs from 'dayjs'

console.log(dayjs(null).format('lll z'));

returned

error TS2769: No overload matches this call.

i tried reproduced this issue. but not reproduced.
but find returned Error in Typescript. so fix it.

give more details for this issue?

[SamuelPoulin]

My bad, I should have mentionned that the z format option is only enabled with advancedFormat. Here's a working example of the issue:

index.js

const dayjs = require("dayjs");

const utc = require("dayjs/plugin/utc");
const timezone = require("dayjs/plugin/timezone");
const advancedFormat = require("dayjs/plugin/advancedFormat");

dayjs.extend(utc)
dayjs.extend(timezone)
// dayjs.extend(advancedFormat) // When this is enabled, dayjs throws. When it's not, it outputs 'Invalid Date'.

console.log(dayjs(null).format('lll z'))

[imwh0im]

i checked plugin advancedFormat.
https://github.com/iamkun/dayjs/blob/dev/src/plugin/advancedFormat/index.js#L12-L51

if you want use the original format(). Do not extend advancedFormat.
Because it changes the function of format() with the plugin advancedFormat.
if you extends advancedFormat. You must to follow the rules.

https://day.js.org/docs/en/plugin/advanced-format check this document.

Apart from this, it seems that the returned values ​​of moment and dayjs are different. so need fix that.
I have the same thoughts as you

[SamuelPoulin]

I completely missed the section in the advancedFormat docs where it says it changes the format function of dayjs. Still, throwing rather than giving Invalid Date is a weird edge case that I'm sure I'm not the only one to catch on deployed code. 😁

I made sure my code does not give a null parameter to an advancedFormat constructor for now, thanks again for working on this

[imwh0im]

Merged complete