fix infinite recursion when custom view type is itself. fixes #4198

CHANGELOG.md

@@ -2,6 +2,7 @@
 next
 ----
 
+- fix infinite recursion when custom view type is itself (#4198)
 - respect firstDay setting when weekNumberCalculation set to ISO (#4734)
 - fix typo in Danish (#4708)
 - adjust typescript def for setExtendedProp (#4679)

packages/__tests__/src/legacy/custom-view-duration.js

@@ -375,4 +375,24 @@ describe('custom view', function() {
       expect($('.fc-crazy-button')).toHaveText('crazy')
     })
   })
+
+  it('throws an error when type is self', function() {
+    let error = null
+
+    try {
+      initCalendar({
+        defaultView: 'month',
+        views: {
+          month: {
+            type: 'month'
+          }
+        }
+      })
+    } catch (_error) {
+      error = _error
+    }
+
+    expect(error).toBeTruthy()
+    expect(error.message).toBe('Can\'t have a custom view type that references itself')
+  })
 })

packages/core/src/structs/view-def.ts

@@ -60,7 +60,16 @@ function buildViewDef(viewType: string, hash: ViewDefHash, defaultConfigs: ViewC
       findViewNameBySubclass(theClass, defaultConfigs)
   }
 
-  let superDef = superType ? ensureViewDef(superType, hash, defaultConfigs, overrideConfigs) : null
+  let superDef: ViewDef | null = null
+
+  if (superType) {
+
+    if (superType === viewType) {
+      throw new Error('Can\'t have a custom view type that references itself')
+    }
+
+    superDef = ensureViewDef(superType, hash, defaultConfigs, overrideConfigs)
+  }
 
   if (!theClass && superDef) {
     theClass = superDef.class