Add support for created and updated at timestamps (#7765)

packages/core/utils/src/dml/entity-builder.ts

@@ -16,11 +16,30 @@ import type {
 } from "./types"
 import { NullableModifier } from "./properties/nullable"
 
+/**
+ * The implicit properties added by EntityBuilder in every schema
+ */
+const IMPLICIT_PROPERTIES = ["created_at", "updated_at", "deleted_at"]
+
 /**
  * Entity builder exposes the API to create an entity and define its
  * schema using the shorthand methods.
  */
 export class EntityBuilder {
+  #disallowImplicitProperties(schema: Record<string, any>) {
+    const implicitProperties = Object.keys(schema).filter((fieldName) =>
+      IMPLICIT_PROPERTIES.includes(fieldName)
+    )
+
+    if (implicitProperties.length) {
+      throw new Error(
+        `Cannot define field(s) "${implicitProperties.join(
+          ","
+        )}" as they are implicitly defined on every model`
+      )
+    }
+  }
+
   /**
    * Define an entity or a model. The name should be unique across
    * all the entities.
@@ -28,12 +47,18 @@ export class EntityBuilder {
   define<
     Schema extends Record<string, PropertyType<any> | RelationshipType<any>>
   >(name: string, schema: Schema) {
+    this.#disallowImplicitProperties(schema)
+
     return new DmlEntity<
       Schema & {
+        created_at: DateTimeProperty
+        updated_at: DateTimeProperty
         deleted_at: NullableModifier<Date, DateTimeProperty>
       }
     >(name, {
       ...schema,
+      created_at: new DateTimeProperty(),
+      updated_at: new DateTimeProperty(),
       deleted_at: new DateTimeProperty().nullable(),
     })
   }

packages/core/utils/src/dml/helpers/create-mikro-orm-entity.ts

@@ -64,6 +64,39 @@ const PROPERTY_TYPES: {
   json: "any",
 }
 
+/**
+ * Properties that needs special treatment based upon their name.
+ * We can safely rely on these names because they are never
+ * provided by the end-user. Instead we output them
+ * implicitly via the DML.
+ */
+const SPECIAL_PROPERTIES: {
+  [propertyName: string]: (
+    MikroORMEntity: EntityConstructor<any>,
+    field: PropertyMetadata
+  ) => void
+} = {
+  created_at: (MikroORMEntity, field) => {
+    Property({
+      columnType: "timestamptz",
+      type: "date",
+      nullable: false,
+      defaultRaw: "now()",
+      onCreate: () => new Date(),
+    })(MikroORMEntity.prototype, field.fieldName)
+  },
+  updated_at: (MikroORMEntity, field) => {
+    Property({
+      columnType: "timestamptz",
+      type: "date",
+      nullable: false,
+      defaultRaw: "now()",
+      onCreate: () => new Date(),
+      onUpdate: () => new Date(),
+    })(MikroORMEntity.prototype, field.fieldName)
+  },
+}
+
 /**
  * Factory function to create the mikro orm entity builder. The return
  * value is a function that can be used to convert DML entities
@@ -92,6 +125,11 @@ export function createMikrORMEntity() {
     MikroORMEntity: EntityConstructor<any>,
     field: PropertyMetadata
   ) {
+    if (SPECIAL_PROPERTIES[field.fieldName]) {
+      SPECIAL_PROPERTIES[field.fieldName](MikroORMEntity, field)
+      return
+    }
+
     /**
      * Defining an enum property
      */