feat: make oneOf relation required if non-nullable

.gitignore

@@ -1,4 +1,5 @@
 node_modules
 lib
 *.log
-coverage
+coverage
+.idea

src/glossary.ts

@@ -225,7 +225,7 @@ export type Value<
     Target[Key] extends OneOf<infer ModelName, infer Nullable>
     ? Nullable extends true
       ? PublicEntity<Dictionary, ModelName> | null
-      : PublicEntity<Dictionary, ModelName> | undefined
+      : PublicEntity<Dictionary, ModelName>
     : // Extract value type from ManyOf relations.
     Target[Key] extends ManyOf<infer ModelName, infer Nullable>
     ? Nullable extends true

src/model/defineRelationalProperties.ts

@@ -9,10 +9,21 @@ import {
   PRIMARY_KEY,
   Value,
 } from '../glossary'
-import { RelationKind, RelationsList } from '../relations/Relation'
+import { Relation, RelationKind, RelationsList } from '../relations/Relation'
 
 const log = debug('defineRelationalProperties')
 
+const getInvariantMessagePrefix = (
+  entity: Entity<any, any>,
+  relation: Relation<any, any, any, any>,
+  propertyPath: string[],
+) =>
+  `Failed to define a "${relation.kind}" relationship to "${
+    relation.target.modelName
+  }" at "${entity[ENTITY_TYPE]}.${propertyPath.join('.')}" (${
+    entity[PRIMARY_KEY]
+  }: "${entity[entity[PRIMARY_KEY]]}")`
+
 export function defineRelationalProperties(
   entity: Entity<any, any>,
   initialValues: Partial<Value<any, ModelDictionary>>,
@@ -23,12 +34,15 @@ export function defineRelationalProperties(
   log('defining relational properties...', { entity, initialValues, relations })
 
   for (const { propertyPath, relation } of relations) {
+    const invariantMessagePrefix = getInvariantMessagePrefix(
+      entity,
+      relation,
+      propertyPath,
+    )
+
     invariant(
       dictionary[relation.target.modelName],
-      'Failed to define a "%s" relational property to "%s" on "%s": cannot find a model by the name "%s".',
-      relation.kind,
-      propertyPath.join('.'),
-      entity[ENTITY_TYPE],
+      `${invariantMessagePrefix}: cannot find a model by the name "%s".`,
       relation.target.modelName,
     )
 
@@ -39,14 +53,14 @@ export function defineRelationalProperties(
 
     invariant(
       references !== null || relation.attributes.nullable,
-      'Failed to define a "%s" relationship to "%s" at "%s.%s" (%s: "%s"): cannot set a non-nullable relationship to null.',
+      `${invariantMessagePrefix}: cannot set a non-nullable relationship to null.`,
+    )
 
-      relation.kind,
-      relation.target.modelName,
-      entity[ENTITY_TYPE],
-      propertyPath.join('.'),
-      entity[PRIMARY_KEY],
-      entity[entity[PRIMARY_KEY]],
+    invariant(
+      relation.kind !== RelationKind.OneOf ||
+        references !== undefined ||
+        relation.attributes.nullable,
+      `${invariantMessagePrefix}: a value must be provided for a non-nullable relationship.`,
     )
 
     log(

test/model/create.test.ts

@@ -1,6 +1,5 @@
 import { faker } from '@faker-js/faker'
-import { factory, primaryKey, oneOf, manyOf, nullable } from '../../src'
-import { identity } from '../../src/utils/identity'
+import { factory, identity, primaryKey, oneOf, manyOf, nullable } from '../../src'
 
 test('creates a new entity', () => {
   const userId = faker.datatype.uuid()
@@ -255,3 +254,23 @@ test('throws an exception when null used as initial value for non-nullable relat
     'Failed to define a "MANY_OF" relationship to "post" at "user.posts" (id: "user-1"): cannot set a non-nullable relationship to null.',
   )
 })
+
+test('throws an exception when value is not provided for a non-nullable oneOf relation', () => {
+  const db = factory({
+    user: {
+      id: primaryKey(String),
+      city: oneOf('city'),
+    },
+    city: {
+      id: primaryKey(String),
+    },
+  })
+
+  expect(() => {
+    db.user.create({
+      id: 'user-1',
+    })
+  }).toThrowError(
+    'Failed to define a "ONE_OF" relationship to "city" at "user.city" (id: "user-1"): a value must be provided for a non-nullable relationship.',
+  )
+})

test/model/relationalProperties.test-d.ts

@@ -8,7 +8,7 @@ const db = factory({
   post: {
     id: primaryKey(String),
     text: String,
-    author: oneOf('user'),
+    author: nullable(oneOf('user')),
     reply: nullable(oneOf('post')),
     likedBy: nullable(manyOf('user')),
   },
@@ -17,7 +17,7 @@ const db = factory({
 const user = db.user.create()
 const post = db.post.create()
 
-// @ts-expect-error author is potentially undefined
+// @ts-expect-error author is potentially null
 post.author.id
 
 // @ts-expect-error reply is potentially null

test/model/relationalProperties.test.ts

@@ -5,7 +5,7 @@ import {
   RelationsList,
 } from '../../src/relations/Relation'
 import { defineRelationalProperties } from '../../src/model/defineRelationalProperties'
-import { testFactory } from '../../test/testUtils'
+import { testFactory } from '../testUtils'
 
 it('marks relational properties as enumerable', () => {
   const { db, dictionary, databaseInstance } = testFactory({
@@ -27,6 +27,7 @@ it('marks relational properties as enumerable', () => {
   const post = db.post.create({
     id: 'post-1',
     title: 'Test Post',
+    author: user,
   })
 
   const relations: RelationsList = [

test/relations/bi-directional.test.ts

@@ -1,13 +1,13 @@
 /**
  * @see https://github.com/mswjs/data/issues/139
  */
-import { factory, manyOf, oneOf, primaryKey } from '@mswjs/data'
+import { factory, manyOf, oneOf, primaryKey, nullable } from '@mswjs/data'
 
 test('supports creating a bi-directional one-to-one relationship', () => {
   const db = factory({
     user: {
       id: primaryKey(String),
-      partner: oneOf('user'),
+      partner: nullable(oneOf('user')),
     },
   })
 
@@ -117,7 +117,7 @@ test('supports querying by a bi-directional one-to-one relationship', () => {
   const db = factory({
     user: {
       id: primaryKey(String),
-      partner: oneOf('user'),
+      partner: nullable(oneOf('user'))
     },
   })
 
@@ -202,8 +202,8 @@ test('supports querying by a bi-directional one-to-many relationship', () => {
   })
 
   // Create unrelated user and post to ensure they are not included.
-  db.user.create({ id: 'user-unrelated' })
-  db.post.create({ id: 'post-unrelated' })
+  const unrelatedUser = db.user.create({ id: 'user-unrelated' })
+  db.post.create({ id: 'post-unrelated', author: unrelatedUser })
 
   // Find posts in one-to-many direction
   const posts = db.post.findMany({
@@ -304,7 +304,7 @@ test('supports updating using an entity with a bi-directional one-to-one relatio
   const db = factory({
     user: {
       id: primaryKey(String),
-      partner: oneOf('user'),
+      partner: nullable(oneOf('user')),
     },
   })
 
@@ -343,7 +343,7 @@ test('supports updating using an entity with a bi-directional one-to-many relati
     post: {
       id: primaryKey(String),
       title: String,
-      author: oneOf('user'),
+      author: nullable(oneOf('user')),
     },
   })
 

test/relations/many-to-one.test.ts

@@ -325,7 +325,7 @@ test('updates a many-to-one relational property without initial value', () => {
     },
     post: {
       id: primaryKey(String),
-      author: oneOf('user'),
+      author: nullable(oneOf('user')),
     },
   })
 
@@ -423,7 +423,7 @@ test('does not throw any error when a many-to-one entity is created without a re
     post: {
       id: primaryKey(String),
       title: String,
-      author: oneOf('user'),
+      author: nullable(oneOf('user')),
     },
   })
 
@@ -437,6 +437,7 @@ test('does not throw any error when a many-to-one entity is created without a re
     [PRIMARY_KEY]: 'id',
     id: 'post-1',
     title: 'First post',
+    author: null,
   })
 })
 

test/relations/one-to-one.create.test.ts

@@ -231,7 +231,7 @@ it('creates a non-nullable relationship', () => {
   ).toEqual(expectedCountry)
 })
 
-it('creates a non-nullable relationship without the initial value', () => {
+it('forbids creating a non-nullable relationship without the initial value', () => {
   const { db, entity } = testFactory({
     country: {
       code: primaryKey(String),
@@ -242,24 +242,13 @@ it('creates a non-nullable relationship without the initial value', () => {
     },
   })
 
-  const country = db.country.create({
-    code: 'uk',
-  })
-
-  const expectedCountry = entity('country', {
-    code: 'uk',
-    capital: undefined,
-  })
-
-  expect(country).toEqual(expectedCountry)
-  expect(db.country.findFirst({ where: { code: { equals: 'uk' } } })).toEqual(
-    expectedCountry,
+  expect(() =>
+    db.country.create({
+      code: 'uk',
+    })
+  ).toThrow(
+    'Failed to define a "ONE_OF" relationship to "city" at "country.capital" (code: "uk"): a value must be provided for a non-nullable relationship.',
   )
-  expect(
-    db.country.findFirst({
-      where: { capital: { name: { equals: 'Manchester' } } },
-    }),
-  ).toEqual(null)
 })
 
 it('forbids creating a non-nullable relationship with null as initial value', () => {
@@ -350,32 +339,6 @@ it('creates a non-nullable unique relationship with initial value', () => {
   ).toEqual(expectedCountry)
 })
 
-it('creates a non-nullable unique relationship without initial value', () => {
-  const { db, entity } = testFactory({
-    country: {
-      code: primaryKey(String),
-      capital: oneOf('city', { unique: true }),
-    },
-    city: {
-      name: primaryKey(String),
-    },
-  })
-
-  const country = db.country.create({
-    code: 'uk',
-  })
-
-  const expectedCountry = entity('country', {
-    code: 'uk',
-    capital: undefined,
-  })
-
-  expect(country).toEqual(expectedCountry)
-  expect(db.country.findFirst({ where: { code: { equals: 'uk' } } })).toEqual(
-    expectedCountry,
-  )
-})
-
 it('forbids creating a unique relationship to already referenced entity', () => {
   const { db } = testFactory({
     country: {

test/relations/one-to-one.operations.test.ts

@@ -53,32 +53,6 @@ it('supports querying through a non-nullable relationship with initial value', (
   ).toEqual(null)
 })
 
-it('supports querying through a non-nullable relationship without initial value', () => {
-  const { db } = testFactory({
-    country: {
-      code: primaryKey(String),
-      capital: oneOf('city'),
-    },
-    city: {
-      name: primaryKey(String),
-    },
-  })
-
-  db.country.create({
-    code: 'uk',
-  })
-
-  // Querying through the relationship is permitted
-  // but since it hasn't been set, no queries will match.
-  expect(
-    db.country.findFirst({
-      where: {
-        capital: { name: { equals: 'London' } },
-      },
-    }),
-  ).toEqual(null)
-})
-
 it('supports querying through a deeply nested non-nullable relationship', () => {
   const { db, entity } = testFactory({
     user: {