Arrow function in twig filter or function returns an error

[JeanLucEsser]

Hi there,

In the same way you added custom twig tags for Craft CMS and others, it would be nice to add custom twig filters (and functions). For example, Craft CMS allows for a few of twig filters in top of twig's defaults as well as some twig functions.

Thanx for everything you bring to the Twig community ;)

[Edit] After some tinkering, this is not the issue. The issue is related to the arrow function (see below).

[JeanLucEsser]

Looks like the issue is not because of an unknown filter but because of the arrow function inside it.

This works:

{% set excludeIds = alerts |group('id') %}

But this won't work:

{% set excludeIds = alerts |group(e => e.alertRef[0].id ?? 0) %}

The culprit is that arrow function e => e.alertRef[0].id.

To be clear, this is not Craft related. Let's take a default twig filter like sort:

{% set alerts = alertsRef|sort((a,b) => a.alertColor <=> b.alertColor) %}

This will return an error.

[rubas]

Upstream Reference: https://github.com/trivago/melody/issues/163