Jira automation| Advanced - How to update the sprint end date in a custom field as a string format

[Karthika Natarajan]

Hi, 

I need help in creating advanced automation for JIRA to update a the sprint end date in a custom field "Target End date" as string.

<span class='inline-description'>The targeted end date. This is a custom field . <span> - Use the d/MMM/yy date format</span></span>

I tried this

{
"update": {
"customfield_12341": [
{
"set": {"value": "{{Issue.sprint.endDate.format("d/MMM/yy")}}"}
}
]
}
}

But i get error "Operation value must be a string (customfield_12341)"

Kindly help.

Thanks,

Karthika