Update custom date field with automation

[Andy Tran]

I'm still new to learning how to use the additional fields for Jira Automation since the fields I'm looking to update are not available in the "Choose fields to set..." drop down.

Problem:  I'm attempting to copy the date value of one custom field over to another custom date field whenever the first custom field is edited but with a different date format.

Data to be copied:

Original Date Field: "2025/10/01"

Copy to new custom date field:

"Customfield_5678": "2025-10-02"

The trigger I'm using is "When: Value changes for"  and does allow me to select the first custom field to monitor for any changes.

However, the "Then" statement needs to be done via JSON in the "additional fields" section.  I cannot figure out how to update the with the same value but in the new format.

[Trudy Claspill]

Hello @Andy Tran 

Welcome to the Atlassian community.

What type of project/space is this automation being used in? Get that information by clicking on the ... button next to the project/space name in the panel on the left. The Space type will display at the bottom of the pop-up and will be something like "Software space Company-managed".

What are the custom field type for each of these fields? Typically in Jira a global date format is applied to all date fields, so I'm trying to understand how you could have to data fields that have different formats.

The formatting commands needed will depend on the types of the custom fields.

[Andy Tran]

It does say "Software space Company-managed" and I'm not entirely sure the custom field types that are being used.  I know the custom field I referenced above "5678" is a date picker so that is definitely a date type field.  The other field is a read only field that is copied into the work item.  Not sure if that is a text field or date field but I'll look into it.

[Andy Tran]

@Trudy Claspill I discovered that the Original Date Field that I'm referencing above is a "Text Field (read only)"

However, if it helps, it's always going to be a date in that format that I listed.  not sure if the automation is still possible

[Trudy Claspill]

Thank you for that additional information.

You said that the field you are trying to set is not a selectable field in your automation.

What is the actual name of that field?

Can you provide a screen image for where you are trying to select that field and not finding it? Date picker fields should be selectable in the Edit Work Item action. You should not have to use JSON to set that type of field.

[Trudy Claspill]

You should be able to select the destination date field from Choose fields to set and then enter a smart value to set it:

{{issue.Original Data Field.toDate("yyyy/MM/dd").jiraDate}}

Replace Original Data Field with the actual name of the source text field.

The .toDate("yyyy/MM/dd") function tells the system that you want to convert the text content of the preceding field to a Date, and the format of the text data is yyyy/MM/dd .

The .jiraDate function tells the system to take the Date object you just created by converting the text and format it to a standard simple Jira date.

That should make the input acceptable for a Data Picker field.

[Andy Tran]

I thought so too but for some reason it's not available making me think that it's a custom field, which I found out that it is by digging through the REST API (which was the result I posted above for custom field).  

[Trudy Claspill]

You may be trying to set the "Target start" built-in field, which is custom but is not the Date Picker custom type. Instead it is the "Target start" custom field type.

I will get back to you on how to set that field with JSON (if one of our other smart community members doesn't beat me to it).

[Andy Tran]

You are correct. That is the field I'm attempting to set.