Incorrect way to updateLocale in moment.js add_inline_script

[yoancutillas]

In [wp-includes/script-loader.php L146](​https://build.trac.wordpress.org/browser/branches/5.7/wp-includes/script-loader.php#L146)

moment.updateLocale( '%s', %s );

WP updates the locale
1. with incomplete data
2. regardless of the existing data

The plugins / themes calling for the removed data expect a String, and they will get an undefined, triggering an Uncaught TypeError for any further process.

This is not too visible yet because of the bug #51142.
But when it will be fixed, a lot of scripts will be affected.

---

1. Incomplete data

1.1
WP currently updates 'longDateFormat' with null parameters. Parameters values should not be null. I suggest to use the 'en_US' values as default.

The parameters should not be null: 'LTS', 'L', 'LLLL'

'longDateFormat' => array(
	'LT'   => get_option( 'time_format', __( 'g:i a', 'default' ) ),
	'LTS'  => null,
	'L'    => null,
	'LL'   => get_option( 'date_format', __( 'F j, Y', 'default' ) ),
	'LLL'  => __( 'F j, Y g:i a', 'default' ),
	'LLLL' => null,
)

1.2
WP currently updates 'week' with 1 parameter instead of 2 (​https://momentjs.com/docs/#/customization/dow-doy/).

Missing parameter: 'doy'

'week' => array(
	'dow' => (int) get_option( 'start_of_week', 0 ),
),

---

2. Existing data

Before calling updateLocale, WP should check if the locale data exists (with moment.localeData( 'en' ) - [docs](​https://momentjs.com/docs/#/i18n/locale-data/)).

I suggest to replace only the missing data, and keep the existing one as is.

[noisysocks]

Thanks for spotting this! The ​fix I opened for #51142 also addresses this.

[mukesh27]

This was discussed in a bug scrub earlier.

Let's set it to Future Release feel free to change the milestone if it is on your to-do list for the next release.

[yoancutillas]

I don't understand, why would you postpone this?

Last week again, another WP user experienced this bug. (​https://wordpress.org/support/topic/js-errors-with-plugin-files/#post-15579274)

The solution was: go to Settings > General > Save changes (without changing any option).
It feels very much like a WP bug, right?

[noisysocks]

I think it would be good to include ​https://github.com/WordPress/wordpress-develop/pull/2456 or some variation of it in 6.1. Just waiting on a code review.

[chaion07]

@yoancutillas thank you for reporting this. We reviewed this ticket during a recent bug-scrub session. Considering the lack of progress on the ticket we are updating the milestone to Future Release. We can always revert back to the current release should there be significant progress in the near future.

Cheers!

Props to @thisisyeasin for the suggestion