Add compile-time type tests for generated loaders

Author: jack-guy

.prettierignore

@@ -1 +1 @@
-flow-typed
+examples/swapi/swapi-loaders.ts

Makefile

@@ -16,11 +16,22 @@ build: node_modules
 	# Generate the .d.ts files
 	node_modules/.bin/tsc --project tsconfig.json --checkJs false --emitDeclarationOnly || true
 
+link-examples: build
+	yarn link
+	cd examples/swapi
+	yarn link dataloader-codegen
+
+build-examples: link-examples
+	$(MAKE) -C examples/swapi swapi-loaders.ts
+	$(MAKE) -C examples/swapi build
+	node examples/swapi/build/swapi-server.js
+
 .PHONY: test
-test: build venv node_modules
+test: build venv node_modules build-examples
 	venv/bin/pre-commit install -f --install-hooks
 	venv/bin/pre-commit run --all-files
 	yarn test
+	yarn test:exampleTypes
 
 .PHONY: clean
 clean:

__tests__/implementation.test.js

@@ -888,15 +888,16 @@ test('batch endpoint with isBatchKeyASet handles a response', async () => {
 
     const resources = {
         foo: ({ foo_ids, include_extra_info }) => {
-            if (_.isEqual(foo_ids, [1, 2])) {
+            expect(foo_ids).toBeInstanceOf(Set);
+            if (_.isEqual(Array.from(foo_ids), [1, 2])) {
                 expect(include_extra_info).toBe(false);
                 return Promise.resolve([
                     { foo_id: 1, foo_value: 'hello' },
                     { foo_id: 2, foo_value: 'world' },
                 ]);
             }
 
-            if (_.isEqual(foo_ids, [3])) {
+            if (_.isEqual(Array.from(foo_ids), [3])) {
                 expect(include_extra_info).toBe(true);
                 return Promise.resolve([
                     {