Migration: Detect and Fix Date Format Strings

Context

Lowdefy v5 uses dayjs instead of moment.js for date formatting — both on date blocks (antd v6) and in the Nunjucks date() filter. Most explicit format strings (e.g., YYYY-MM-DD) are compatible, but moment.js locale shortcuts render as literal characters in dayjs and must be replaced with explicit format tokens.

What to Do

Part 1 — Nunjucks date() filter: Replace locale shortcuts (auto-fix)

Moment.js locale shortcuts (l, ll, lll, llll and uppercase L, LL, LLL, LLLL) are not supported by dayjs in the Nunjucks date() filter. They render as literal characters (e.g., dates show as "llll" instead of a formatted date).

Replace these with explicit dayjs format tokens:

Files to search:

Glob: **/*.{yaml,yml,yaml.njk} Grep: date\(['"]([lL]{1,4}|LTS?)['"]\)

Example:

Before:

template: "{{ meeting_date | date('llll') }}"

After:

template: "{{ meeting_date | date('ddd, D MMM YYYY h:mm A') }}"

Before:

Last modified by {{ doc.updated.user.name | safe }} on {{ doc.updated.timestamp | date('lll')}}

After:

Last modified by {{ doc.updated.user.name | safe }} on {{ doc.updated.timestamp | date('D MMM YYYY h:mm A')}}

Part 2 — Date block format properties: Review (report-only)

Find custom date format strings on date blocks and verify they work with dayjs. Standard formats need no changes.

Affected blocks: DateSelector, DateRangeSelector, DateTimeSelector, MonthSelector, WeekSelector.

Standard formats (no action needed):

• YYYY-MM-DD
• YYYY-MM-DD HH:mm:ss
• YYYY-MM-DD HH:mm
• HH:mm:ss
• HH:mm

Formats to check:

• Custom format strings that aren't in the standard list above
• Moment-specific tokens: Mo (ordinal month), Do (ordinal day), Qo (ordinal quarter)

Files to search:

Glob: **/*.{yaml,yml} Grep: type: DateSelector|type: DateRangeSelector|type: DateTimeSelector|type: MonthSelector|type: WeekSelector

Then look for format: properties within those blocks.

Examples

No action needed

- id: start_date
  type: DateSelector
  properties:
    format: YYYY-MM-DD

Needs review

- id: display_date
  type: DateSelector
  properties:
    format: Do MMMM YYYY

Do (ordinal day like "1st", "2nd") requires the dayjs advancedFormat plugin. Verify it renders correctly.

Operator expression — skip

- id: dynamic_date
  type: DateSelector
  properties:
    format:
      _state: dateFormat

Skip operator expressions — they'll resolve at runtime.

Edge Cases

• Part 1 (Nunjucks locale shortcuts) is an auto-fix — the replacements are safe to apply
• Part 2 (date block formats) is report-only — don't change format strings automatically
• Most moment format tokens work identically in dayjs
• The Do, Mo, Qo ordinal tokens require dayjs's advancedFormat plugin (bundled by Lowdefy)
• X (unix timestamp) and x (millisecond timestamp) work in both

Verification

After applying Part 1 replacements, verify date rendering in the app. Part 2 is informational — the user should test any flagged date blocks after the upgrade.