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

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

[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]

Merged complete