fix: guard against null/undefined in getTag function

- Add null check at the top of getTag to return empty object early,
  preventing TypeError when Object.entries receives null or undefined
  (typeof null === "object" in JS, so null slipped through the switch)
- Add test cases covering null/undefined field values, null/undefined
  entries, multiple null fields, and nested null objects (Issue #193)

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: nadeem-cs

__test__/entry-editable.test.ts

@@ -519,6 +519,77 @@ describe('Entry editable test', () => {
         })
     })
 
+    describe('Null and undefined content handling (Issue #193)', () => {
+        it('should not throw when entry has a null field value', done => {
+            const entryWithNullField: any = {
+                "uid": "entry_uid_null",
+                "locale": "en-us",
+                "title": "Valid title",
+                "description": null
+            }
+
+            expect(() => addTags(entryWithNullField, 'content_type', false)).not.toThrow()
+            expect((entryWithNullField as any)['$']['title']).toEqual('data-cslp=content_type.entry_uid_null.en-us.title')
+            done()
+        })
+
+        it('should not throw when entry has an undefined field value', done => {
+            const entryWithUndefinedField: any = {
+                "uid": "entry_uid_undef",
+                "locale": "en-us",
+                "title": "Valid title",
+                "description": undefined
+            }
+
+            expect(() => addTags(entryWithUndefinedField, 'content_type', false)).not.toThrow()
+            expect((entryWithUndefinedField as any)['$']['title']).toEqual('data-cslp=content_type.entry_uid_undef.en-us.title')
+            done()
+        })
+
+        it('should return empty tags for a null entry', done => {
+            const nullEntry: any = null
+
+            expect(() => addTags(nullEntry, 'content_type', false)).not.toThrow()
+            done()
+        })
+
+        it('should return empty tags for an undefined entry', done => {
+            const undefinedEntry: any = undefined
+
+            expect(() => addTags(undefinedEntry, 'content_type', false)).not.toThrow()
+            done()
+        })
+
+        it('should handle entry with multiple null field values', done => {
+            const entryWithMultipleNulls: any = {
+                "uid": "entry_uid_multi_null",
+                "locale": "en-us",
+                "title": "Valid title",
+                "field_a": null,
+                "field_b": null,
+                "field_c": "valid"
+            }
+
+            expect(() => addTags(entryWithMultipleNulls, 'content_type', true)).not.toThrow()
+            expect((entryWithMultipleNulls as any)['$']['title']).toEqual({'data-cslp': 'content_type.entry_uid_multi_null.en-us.title'})
+            expect((entryWithMultipleNulls as any)['$']['field_c']).toEqual({'data-cslp': 'content_type.entry_uid_multi_null.en-us.field_c'})
+            done()
+        })
+
+        it('should handle entry with nested null object', done => {
+            const entryWithNestedNull: any = {
+                "uid": "entry_uid_nested_null",
+                "locale": "en-us",
+                "title": "Valid title",
+                "group": null
+            }
+
+            expect(() => addTags(entryWithNestedNull, 'content_type', false)).not.toThrow()
+            expect((entryWithNestedNull as any)['$']['title']).toEqual('data-cslp=content_type.entry_uid_nested_null.en-us.title')
+            done()
+        })
+    })
+
     describe('useLowerCaseLocale option', () => {
         it('should preserve locale casing when useLowerCaseLocale is false', done => {
             const entry = {

src/entry-editable.ts

@@ -34,6 +34,9 @@ export function addTags(entry: EntryModel, contentTypeUid: string, tagsAsObject:
 }
 
 function getTag(content: object, prefix: string, tagsAsObject: boolean, locale: string, appliedVariants: AppliedVariants): object {
+    if (content == null) {
+        return {}
+    }
     const tags: any = {}
     const { metaKey, shouldApplyVariant, _applied_variants } = appliedVariants
     Object.entries(content).forEach(([key, value]) => {