Editorial: Algorithmic approach for early returns in UnbalanceDateDur…

…ationRelative

spec/duration.html

@@ -1363,14 +1363,9 @@ <h1>
         <dd>It converts the calendar units of a duration into a form where no unit is larger than _largestUnit_, and returns the result as a Date Duration Record.</dd>
       </dl>
       <emu-alg>
-        1. If _largestUnit_ is *"year"*, then
+        1. Let _defaultLargestUnit_ be DefaultTemporalLargestUnit(_years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0).
+        1. If _largestUnit_ is LargerOfTwoTemporalUnits(_defaultLargestUnit_, _largestUnit_), then
           1. Return ! CreateDateDurationRecord(_years_, _months_, _weeks_, _days_).
-        1. Else if _largestUnit_ is *"month"* and _years_ = 0, then
-          1. Return ! CreateDateDurationRecord(0, _months_, _weeks_, _days_).
-        1. Else if _largestUnit_ is *"week"* and _years_ = 0 and _months_ = 0, then
-          1. Return ! CreateDateDurationRecord(0, 0, _weeks_, _days_).
-        1. Else if _largestUnit_ is *"day"* and _years_ = 0 and _months_ = 0 and _weeks_ = 0, then
-          1. Return ! CreateDateDurationRecord(0, 0, 0, _days_).
         1. Let _sign_ be ! DurationSign(_years_, _months_, _weeks_, _days_, 0, 0, 0, 0, 0, 0).
         1. Assert: _sign_ &ne; 0.
         1. Let _oneYear_ be ! CreateTemporalDuration(_sign_, 0, 0, 0, 0, 0, 0, 0, 0, 0).