Forces nullable batchKeys to be non-nullable (#339)

* Forces nullable batchKeys to be non-nullable

* Adds a test to ensure null batchKeys would throw a TypeError

* Update __tests__/implementation.test.js

Co-authored-by: Yue Guo <[email protected]>

Co-authored-by: Yue Guo <[email protected]>

Author: quantsini

__tests__/genTypeFlow.test.js

@@ -1,4 +1,4 @@
-import { getResourceTypeReference, getNewKeyTypeFromBatchKeySetType } from '../src/genTypeFlow';
+import { getResourceTypeReference, getNewKeyTypeFromBatchKeySetType, getLoaderTypeKey } from '../src/genTypeFlow';
 
 it('getResourceTypeReference converts a resource path to a valid reference', () => {
     expect(getResourceTypeReference(null, ['foo', 'bar', 'baz'])).toBe(
@@ -18,3 +18,30 @@ it('getNewKeyTypeFromBatchKeySetType returns a newKey type with a valid value',
             [$PropertyType<$PropertyType<$PropertyType<$PropertyType<$PropertyType<ResourcesType, 'foo'>, 'bar'>, 'baz'>, 'bKey'>, 'has'>]
         >`);
 });
+
+it('getLoaderTypeKey forces a nullable batchKey to be strictly non-nullable', () => {
+    expect(
+        getLoaderTypeKey(
+            {
+                isBatchResource: true,
+                newKey: 'test_id',
+                batchKey: 'test_ids',
+            },
+            ['a', 'b'],
+        ),
+    ).toBe(`\{|
+            ...$Diff<        $Call<
+            ExtractArg,
+            [$PropertyType<$PropertyType<ResourcesType, 'a'>, 'b'>]
+        >, {
+                test_ids: $PropertyType<        $Call<
+            ExtractArg,
+            [$PropertyType<$PropertyType<ResourcesType, 'a'>, 'b'>]
+        >, 'test_ids'>
+            }>,
+            ...{| test_id: $NonMaybeType<$ElementType<$PropertyType<        $Call<
+            ExtractArg,
+            [$PropertyType<$PropertyType<ResourcesType, 'a'>, 'b'>]
+        >, 'test_ids'>, 0>> |}
+        |}`);
+});

__tests__/implementation.test.js

@@ -130,6 +130,34 @@ test('batch endpoint', async () => {
     });
 });
 
+test("batch endpoint can't be called with null", async () => {
+    const config = {
+        resources: {
+            foo: {
+                isBatchResource: true,
+                docsLink: 'example.com/docs/bar',
+                batchKey: 'foo_ids',
+                newKey: 'foo_id',
+            },
+        },
+    };
+
+    const resources = {
+        foo: ({ foo_ids }) => {
+            expect(foo_ids).toEqual([1]);
+            return Promise.resolve([{ foo_id: 1, foo_value: 'hello' }]);
+        },
+    };
+
+    await createDataLoaders(config, async (getLoaders) => {
+        const loaders = getLoaders(resources);
+
+        expect(() => {
+            loaders.foo.load(null);
+        }).toThrow(TypeError);
+    });
+});
+
 test('batch endpoint (with reorderResultsByKey)', async () => {
     const config = {
         resources: {

src/genTypeFlow.ts

@@ -55,7 +55,8 @@ export function getLoaderTypeKey(resourceConfig: ResourceConfig, resourcePath: R
 
     if (resourceConfig.isBatchResource) {
         // Extract newKeyType from the batch key's Array's type
-        let newKeyType = `${resourceConfig.newKey}: $ElementType<$PropertyType<${resourceArgs}, '${resourceConfig.batchKey}'>, 0>`;
+        // We add NonMaybeType before batch key element type to force the batch key to be required, regardless if the OpenAPI spec specifies it as being optional
+        let newKeyType = `${resourceConfig.newKey}: $NonMaybeType<$ElementType<$PropertyType<${resourceArgs}, '${resourceConfig.batchKey}'>, 0>>`;
 
         if (resourceConfig.isBatchKeyASet) {
             /**