feat: customId function

Author: =

packages/language/res/stdlib.zmodel

@@ -104,6 +104,13 @@ function nanoid(length: Int?, format: String?): String {
 function ulid(format: String?): String {
 } @@@expressionContext([DefaultValue])
 
+/**
+ * Generates a custom identifier. The ORM client must be initialized with an
+ * implementation of this function.
+ */
+function customId(length: Int?): String {
+} @@@expressionContext([DefaultValue])
+
 /**
  * Creates a sequence of integers in the underlying database and assign the incremented
  * values to the ID values of the created records based on the sequence.

packages/orm/src/client/crud/operations/base.ts

@@ -1044,7 +1044,7 @@ export abstract class BaseOperationHandler<Schema extends SchemaDef> {
             }
             if (!(field in data)) {
                 if (typeof fieldDef?.default === 'object' && 'kind' in fieldDef.default) {
-                    const generated = this.evalGenerator(fieldDef.default);
+                    const generated = this.evalGenerator(fieldDef.default, modelDef.name);
                     if (generated !== undefined) {
                         values[field] = this.dialect.transformInput(
                             generated,
@@ -1072,7 +1072,7 @@ export abstract class BaseOperationHandler<Schema extends SchemaDef> {
         return values;
     }
 
-    private evalGenerator(defaultValue: Expression) {
+    private evalGenerator(defaultValue: Expression, model: string) {
         if (ExpressionUtils.isCall(defaultValue)) {
             const firstArgVal =
                 defaultValue.args?.[0] && ExpressionUtils.isLiteral(defaultValue.args[0])
@@ -1095,6 +1095,16 @@ export abstract class BaseOperationHandler<Schema extends SchemaDef> {
                     return this.formatGeneratedValue(generated, defaultValue.args?.[1]);
                 })
                 .with('ulid', () => this.formatGeneratedValue(ulid(), defaultValue.args?.[0]))
+                .with('customId', () => {
+                    invariant(this.client.$options.customId, '"customId" implementation not provided');
+                    const length = typeof firstArgVal === 'number' ? firstArgVal : undefined;
+                    const generated = this.client.$options.customId({
+                        model,
+                        length,
+                    });
+                    invariant(generated && typeof generated === 'string', '"customId" must return a non-empty string');
+                    return generated;
+                })
                 .otherwise(() => undefined);
         } else if (
             ExpressionUtils.isMember(defaultValue) &&

packages/orm/src/client/options.ts

@@ -40,6 +40,20 @@ export type ZModelFunction<Schema extends SchemaDef> = (
     context: ZModelFunctionContext<Schema>,
 ) => Expression<unknown>;
 
+export type CustomIdFunctionContext = {
+    /**
+     * The model for which the ID should be generated for.
+     */
+    model: string;
+
+    /**
+     * The requested length of the ID.
+     */
+    length?: number;
+};
+
+export type CustomIdFunction = (ctx: CustomIdFunctionContext) => string;
+
 /**
  * ZenStack client options.
  */
@@ -82,6 +96,12 @@ export type ClientOptions<Schema extends SchemaDef> = {
      */
     validateInput?: boolean;
 
+    /**
+     * Implementation of a custom ID generation function, which is called from ZModel as
+     * `@default(customId())`.
+     */
+    customId?: CustomIdFunction;
+
     /**
      * Options for omitting fields in ORM query results.
      */