Display date from selected tasks in the portfolio

This article explains how to automatically display the due date of a task in the project data — by marking the task with a label. This technique is ideal for milestones like Project Start, GoLive, Project End, or other important dates.

The implementation consists of two separate formula flavors:

• Flavor 1: Determines the task’s due date and stores it as a timestamp.
• Flavor 2: Reads the stored timestamp from Flavor 1 and displays either a date or an error message.

Important: Both formulas/flavors are created in the project master data.
The following examples show the functionality in three levels of complexity — from simple to fully automated pro logic.

Part 1 – Determine the date from tasks & store it as a timestamp

Flavor 1 generates a timestamp from a task’s due date. This value is stored and later displayed by Flavor 2.

Level 1 – Simplest version (no label, no validation)

This formula stores the due date of all tasks as a timestamp. Only suitable when there is exactly one relevant task.

persist(
  sumAll(toTimestamp(duedate))
)

Level 2 – Filter by label

This version only considers tasks that contain a specific label ID.

You can find the label ID in two ways:

• In a task that contains the desired label — click the label and select Copy GUID.
• In the Label Manager — open the label, click Configure, then select Copy GUID.
  
   

persist(
  sumAll('
    if(contains(labelIds, "<LABEL-ID>", 1),
       toTimestamp(duedate),
       0)
  ')
)

Replace: <LABEL-ID> → technical ID of the desired label.

Level 3 – Pro version (full validation)

This version includes full logic with error detection:

• Multiple tasks have the same label → error code -1
• Exactly one task has the label → store date as timestamp

persist(
  if(
    sumAll('if(contains(labelIds, "<LABEL-ID>", 1), 1, 0)', 0) > 1,
    -1,
    sumAll('
      if(contains(labelIds, "<LABEL-ID>", 1),
         toTimestamp(duedate),
         0)
    ', 0)
  )
)

Part 2 – Display the stored timestamp as a date

Flavor 2 reads the result from Flavor 1 (e.g. from a field like <TIMESTAMP-FIELD>) and displays it in a readable format.

Level 1 – Simple conversion (no validation)

shortDate(
  fromTimestamp(
    flavor("<SavedDate>")
  )
)

Simply displays the stored date.

Level 2 – Warning when no date is set

if(
  flavor("<SavedDate>") == 0,
  "No date set",
  shortDate(fromTimestamp(flavor("<SavedDate>")))
)

Level 3 – Pro version (complete error logic)

This version detects:

• -1 → Multiple tasks are marked
• 0 or smaller → No date set
• Positive value → valid timestamp

if(
  flavor("<SavedDate>") == -1,
  "Date not uniquely defined (multiple tasks marked)",
  if(
    flavor("<SavedDate>") == 0 || flavor("<SavedDate>") < -1,
    "No date defined yet",
    shortDate(
      fromTimestamp(flavor("<SavedDate>") - 2*60*60*1000)
    )
  )
)