Allow a arbitrary equality comparison function to be passed in the column options

src/orm/base_model/index.ts

@@ -1348,9 +1348,15 @@ class BaseModelImpl implements LucidRow {
     const dirty = Object.keys(this.$attributes).reduce((result: any, key) => {
       const value = this.$attributes[key]
       const originalValue = this.$original[key]
+
+      const Model = this.constructor as LucidModel
+      const column = Model.$getColumn(key)
+
       let isEqual = true
 
-      if (isObject(value) && 'isDirty' in value) {
+      if (column?.equals) {
+        isEqual = column.equals(originalValue, value)
+      } else if (isObject(value) && 'isDirty' in value) {
         isEqual = !value.isDirty
       } else {
         isEqual = compareValues(originalValue, value)

src/types/model.ts

@@ -216,6 +216,11 @@ export type ColumnOptions = {
    * Invoked when row is fetched from the database
    */
   consume?: (value: any, attribute: string, model: LucidRow) => any
+
+  /**
+   * Invoked to compare to values for equality when tracking dirty attributes
+   */
+  equals?: (a: any, b: any) => boolean
 }
 
 /**

test/orm/base_model.spec.ts

@@ -813,6 +813,36 @@ test.group('Base Model | dirty', (group) => {
     user.location.isDirty = true
     assert.deepEqual(user.$dirty, { location: { state: 'goa', country: 'India', isDirty: true } })
   })
+
+  test('compute diff for properties using equals column option', async ({ fs, assert }) => {
+    const app = new AppFactory().create(fs.baseUrl, () => {})
+    await app.init()
+    const adapter = new FakeAdapter()
+
+    const BaseModel = getBaseModel(adapter)
+
+    class User extends BaseModel {
+      @column()
+      declare username: string
+
+      @column()
+      declare age: number
+
+      @column({
+        equals: (a: Set<string>, b: Set<string>) =>
+          a.size === b.size && Array.from(a).every((item) => b.has(item)),
+      })
+      colors: Set<string> = new Set()
+    }
+    User.$adapter = adapter
+
+    const user = new User()
+    user.username = 'virk'
+    user.colors = new Set(['red', 'green', 'blue'])
+
+    assert.isTrue(user.$isDirty)
+    assert.isTrue(!!user.$dirty.colors)
+  })
 })
 
 test.group('Base Model | persist', (group) => {