Explicitly check for undefined

catamorphism · ptomato · commit 12a306e81d6a · 2026-01-12T16:27:32.000-08:00
diff --git a/polyfill/lib/calendar.mjs b/polyfill/lib/calendar.mjs
@@ -1951,7 +1951,7 @@ const helperChinese = ObjectAssign({}, nonIsoHelperBase, {
     }
   },
   getMonthList(calendarYear, cache) {
-    assert(calendarYear, 'getMonthList called on undefined year');
+    assert(calendarYear !== undefined, 'getMonthList called on undefined year');
     const key = OneObjectCache.generateMonthListKey(calendarYear);
     const cached = cache.get(key);
     if (cached) return cached;

Original file line number	Diff line number	Diff line change
`@@ -1951,7 +1951,7 @@ const helperChinese = ObjectAssign({}, nonIsoHelperBase, {`
`1951`	`1951`	`}`
`1952`	`1952`	`},`
`1953`	`1953`	`getMonthList(calendarYear, cache) {`
`1954`		`- assert(calendarYear, 'getMonthList called on undefined year');`
	`1954`	`+ assert(calendarYear !== undefined, 'getMonthList called on undefined year');`
`1955`	`1955`	`const key = OneObjectCache.generateMonthListKey(calendarYear);`
`1956`	`1956`	`const cached = cache.get(key);`
`1957`	`1957`	`if (cached) return cached;`