validate computed field configuration on startup

packages/orm/src/client/client-impl.ts

@@ -75,6 +75,11 @@ export class ClientImpl {
             ...this.$options.functions,
         };
 
+        if (!baseClient) {
+            // validate computed fields configuration once for the root client
+            this.validateComputedFieldsConfig();
+        }
+
         // here we use kysely's props constructor so we can pass a custom query executor
         if (baseClient) {
             this.kyselyProps = {
@@ -139,6 +144,39 @@ export class ClientImpl {
         return new ClientImpl(this.schema, this.$options, this, executor);
     }
 
+    /**
+     * Validates that all computed fields in the schema have corresponding configurations.
+     */
+    private validateComputedFieldsConfig() {
+        const computedFieldsConfig =
+            'computedFields' in this.$options
+                ? (this.$options.computedFields as Record<string, any> | undefined)
+                : undefined;
+
+        for (const [modelName, modelDef] of Object.entries(this.$schema.models)) {
+            if (modelDef.computedFields) {
+                for (const fieldName of Object.keys(modelDef.computedFields)) {
+                    const modelConfig = computedFieldsConfig?.[modelName];
+                    const fieldConfig = modelConfig?.[fieldName];
+                    // Check if the computed field has a configuration
+                    if (fieldConfig === null || fieldConfig === undefined) {
+                        throw createConfigError(
+                            `Computed field "${fieldName}" in model "${modelName}" does not have a configuration. ` +
+                                `Please provide an implementation in the computedFields option.`,
+                        );
+                    }
+                    // Check that the configuration is a function
+                    if (typeof fieldConfig !== 'function') {
+                        throw createConfigError(
+                            `Computed field "${fieldName}" in model "${modelName}" has an invalid configuration: ` +
+                                `expected a function but received ${typeof fieldConfig}.`,
+                        );
+                    }
+                }
+            }
+        }
+    }
+
     // overload for interactive transaction
     $transaction<T>(
         callback: (tx: ClientContract<SchemaDef>) => Promise<T>,

tests/e2e/orm/client-api/computed-fields.test.ts

@@ -3,6 +3,94 @@ import { sql } from 'kysely';
 import { describe, expect, it } from 'vitest';
 
 describe('Computed fields tests', () => {
+    it('throws error when computed field configuration is missing', async () => {
+        await expect(
+            createTestClient(
+                `
+model User {
+    id Int @id @default(autoincrement())
+    name String
+    upperName String @computed
+}
+`,
+                {
+                    // missing computedFields configuration
+                } as any,
+            ),
+        ).rejects.toThrow('Computed field "upperName" in model "User" does not have a configuration');
+    });
+
+    it('throws error when computed field is missing from configuration', async () => {
+        await expect(
+            createTestClient(
+                `
+model User {
+    id Int @id @default(autoincrement())
+    name String
+    upperName String @computed
+    lowerName String @computed
+}
+`,
+                {
+                    computedFields: {
+                        User: {
+                            // only providing one of two computed fields
+                            upperName: (eb: any) => eb.fn('upper', ['name']),
+                        },
+                    },
+                } as any,
+            ),
+        ).rejects.toThrow('Computed field "lowerName" in model "User" does not have a configuration');
+    });
+
+    it('throws error when computed field configuration is not a function', async () => {
+        await expect(
+            createTestClient(
+                `
+model User {
+    id Int @id @default(autoincrement())
+    name String
+    upperName String @computed
+}
+`,
+                {
+                    computedFields: {
+                        User: {
+                            // providing a string instead of a function
+                            upperName: 'not a function' as any,
+                        },
+                    },
+                } as any,
+            ),
+        ).rejects.toThrow(
+            'Computed field "upperName" in model "User" has an invalid configuration: expected a function but received string',
+        );
+    });
+
+    it('throws error when computed field configuration is a non-function object', async () => {
+        await expect(
+            createTestClient(
+                `
+model User {
+    id Int @id @default(autoincrement())
+    name String
+    computed1 String @computed
+}
+`,
+                {
+                    computedFields: {
+                        User: {
+                            // providing an object instead of a function
+                            computed1: { key: 'value' } as any,
+                        },
+                    },
+                } as any,
+            ),
+        ).rejects.toThrow(
+            'Computed field "computed1" in model "User" has an invalid configuration: expected a function but received object',
+        );
+    });
+
     it('works with non-optional fields', async () => {
         const db = await createTestClient(
             `
@@ -102,6 +190,11 @@ model User {
 }
 `,
             {
+                computedFields: {
+                    User: {
+                        upperName: (eb: any) => eb.fn('upper', ['name']),
+                    },
+                },
                 extraSourceFiles: {
                     main: `
 import { ZenStackClient } from '@zenstackhq/orm';
@@ -169,6 +262,11 @@ model User {
 }
 `,
             {
+                computedFields: {
+                    User: {
+                        upperName: (eb: any) => eb.lit(null),
+                    },
+                },
                 extraSourceFiles: {
                     main: `
 import { ZenStackClient } from '@zenstackhq/orm';