Problem/Motivation

In the core, to get the last item in an array, use array[array.length - 1]. Modern JavaScript makes this code shorter.

Proposed resolution

Use array.at(-1).
For example, in /themes/claro/js/mobile.install.js

Before:

    if (steps[steps.length - 1].className === 'done') {

After:

    if (steps.at(-1).className === 'done') {

Remaining tasks

User interface changes

API changes

Data model changes

Release notes snippet

CommentFileSizeAuthor
#13 3576258-nr-bot__798btmo.txt961 bytesneeds-review-queue-bot
#8 Screenshot 2026-04-06 at 1.53.57 PM.png71.27 KBsmustgrave

Issue fork drupal-3576258

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Comments

tom konda created an issue. See original summary.

tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Assigned: Unassigned » tom konda
tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Parent issue: » #3571412: [Meta] Modernize JavaScript value assignment to some of variables

tom konda changed the visibility of the branch 3576258-prefer-to-replace to hidden.

tom konda opened merge request !14944

tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Assigned: tom konda » Unassigned
Status: Active » Needs work
tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Status: Needs work » Needs review
smustgrave’s picture

smustgrave commented
Status: Needs review » Needs work
StatusFileSize
new Screenshot 2026-04-06 at 1.53.57 PM.png71.27 KB

With the addition of default_admin believe there are other instances now.

more

tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Status: Needs work » Needs review

Replaced array[array.length - 1] in default_admin theme.

smustgrave’s picture

smustgrave commented
Status: Needs review » Reviewed & tested by the community
Issue tags: +Needs Review Queue Initiative

Additional ones appear to be addressed.

quietone’s picture

quietone commented
Status: Reviewed & tested by the community » Needs work

What about this instance?

$ git grep  ".length - 1]"  | grep -v core/assets
core/modules/navigation/js/arrow-navigation.js:              elements[elements.length - 1].focus();

Is there a linting rule that can enforce this?

tom konda’s picture

tom konda
Primary language Japanese
Location Kanagawa, Japan
commented
Status: Needs work » Needs review

> What about this instance?

Fixed it.

> Is there a linting rule that can enforce this?

No, in the ESLint standard rules.

needs-review-queue-bot’s picture

needs-review-queue-bot commented
Status: Needs review » Needs work
StatusFileSize
new 3576258-nr-bot__798btmo.txt961 bytes

The Needs Review Queue Bot tested this issue. It fails the Drupal core commit checks. Therefore, this issue status is now "Needs work".

This does not mean that the patch necessarily needs to be re-rolled or the MR rebased. Read the Issue Summary, the issue tags and the latest discussion here to determine what needs to be done.

Consult the Drupal Contributor Guide to find step-by-step guides for working with issues.