Fix Persist compatibility with older Alpine versions

Author: calebporzio

packages/persist/src/index.js

@@ -17,7 +17,7 @@ export default function (Alpine) {
             }
         }
 
-        return Alpine.interceptor((initialValue, getter, setter, path, key, cleanup) => {
+        return Alpine.interceptor((initialValue, getter, setter, path, key, cleanup = () => {}) => {
             let lookup = alias || `_x_${path}`
 
             let initial = storageHas(lookup, storage)

tests/vitest/persist.spec.js

@@ -0,0 +1,53 @@
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import persist from '../../packages/persist/src/index.js'
+
+describe('persist', () => {
+    afterEach(() => vi.unstubAllGlobals())
+
+    it('supports Alpine versions without interceptor cleanup', () => {
+        let values = new Map()
+        let storage = {
+            getItem: key => values.get(key) ?? null,
+            setItem: (key, value) => values.set(key, value),
+        }
+        let data = { count: 0 }
+
+        vi.stubGlobal('localStorage', storage)
+
+        let Alpine = {
+            effect(callback) {
+                callback()
+            },
+            interceptor(callback, mutate) {
+                let interceptor = {
+                    initialize(data, path, key) {
+                        return callback(
+                            this.initialValue,
+                            () => data[path],
+                            value => data[path] = value,
+                            path,
+                            key,
+                        )
+                    },
+                }
+
+                mutate(interceptor)
+
+                return initialValue => {
+                    interceptor.initialValue = initialValue
+
+                    return interceptor
+                }
+            },
+            magic() {},
+        }
+
+        persist(Alpine)
+
+        let value = Alpine.$persist(1)
+
+        expect(value.initialize(data, 'count', 'count')).toBe(1)
+        expect(data.count).toBe(1)
+        expect(storage.getItem('_x_count')).toBe('1')
+    })
+})