Fix ordinal superscript for numbers ending in 0 (20th, 30th, etc.)

[gabesl]

Fix: Ordinal superscript not applied to numbers ending in 0 (20th, 30th, 40th, etc.)

Problem

When typing ordinal numbers ending in 0 (20th, 30th, 40th, 50th, etc.) in the editor, the superscript formatting is not applied to the suffix ("th"). Other ordinals like 1st-19th, 21st-29th, 31st-39th work correctly.

Additionally, the same issue occurs when the number and suffix are in separate segments, such as when a number is hyperlinked followed by an unlinked ordinal suffix (e.g., 20th).

Root Cause

In transformOrdinals.ts, the code uses falsy checks (&&) to validate numeric values:

• Line 43: (numericValue = getNumericValue(...)) &&
• Line 51: if (numericValue && getOrdinal(numericValue) === ordinal)

For numbers ≥20, getNumericValue() extracts the last digit to determine the ordinal suffix. When that digit is 0, the function correctly returns 0, but the falsy check treats 0 as false, causing the superscript logic to be skipped even though 0 is a valid numeric result.

Solution

Changed both falsy checks to explicit null checks:

• Line 43: (numericValue = getNumericValue(...)) !== null &&
• Line 51: if (numericValue !== null && getOrdinal(numericValue) === ordinal)

This allows 0 to be treated as a valid numeric value while still rejecting actual null/undefined values.

Testing

• ✅ Manually tested in demo site: 20th, 30th, 40th, 50th, 60th all now apply superscript correctly
• ✅ Manually tested: 21st, 22nd, 23rd, 24th still work correctly (regression check)
• ✅ Manually tested: Space-separated case "20 th" now works
• ✅ Logic verification: Created test script confirming numeric extraction and ordinal matching work correctly for all cases

Changes

• Modified 2 lines in packages/roosterjs-content-model-plugins/lib/autoFormat/numbers/transformOrdinals.ts
• No breaking changes
• Backward compatible with all existing functionality

[BryanValverdeU]

Please add unit test for the scenario being fixed.