Typechecking performance regression in @golevelup/ts-jest createMock() #1139
Description
I was upgrading from version 0.5.6 to 1.2.1 and noticed that the editor felt rather sluggish. When tracing tsc, I found that our test files containing createMock() took quite some time to finish type checking.
For example, here is one of our test files:
import { createMock } from '@golevelup/ts-jest';
import { getQueueToken } from '@nestjs/bullmq';
import { Test } from '@nestjs/testing';
import { BloomreachConfigService } from '@newseditor/bloomreach';
import { DatabaseModule } from '@newseditor/database';
import { JobQueues } from '@newseditor/job-queue';
import { RedisModule } from '@newseditor/redis';
import { SearchNodeModule } from '@newseditor/search-node';
import { AiTranslationConfig } from '@newseditor/translator';
import { BackendModule } from './backend.module';
describe('BackendModule', () => {
it('should be imported without errors', async () => {
let testingModule = Test.createTestingModule({
imports: [BackendModule],
})
.overrideModule(DatabaseModule)
.useModule(DatabaseModule.forPrismaClient(createMock()))
.overrideModule(RedisModule)
.useModule(RedisModule.forRedisClient(createMock()))
.overrideModule(SearchNodeModule)
.useModule(
SearchNodeModule.forConfig({
openSearchClient: createMock(),
searchConfig: { url: '', packagePath: null, index: 'test', configurationTarget: 'test_v0' },
}),
)
// Mock the BullMQ queues
for (const queueName of Object.values(JobQueues)) {
testingModule = testingModule.overrideProvider(getQueueToken(queueName)).useValue(createMock());
}
await testingModule.compile();
});
});The three important calls here are DatabaseModule.forPrismaClient(createMock()) which expects a PrismaClient instance, RedisModule.forRedisClient(createMock()) expecting a Client from ioredis, and (by far the worst offender) SearchNodeModule.forConfig({ openSearchClient: createMock() }) expecing a Client from @opensearch-project/opensearch.
Type-checking this file using this command:
pnpm tsc --noEmit --project ./apps/backend/tsconfig.spec.json --extendedDiagnostics --generateTrace ./name-of-folder
I noticed that this file alone takes around 450ms to type-check. I then went back to the old version and measured only around 160ms.
By installing versions 1.2.0 -> 0.5.7 of @golevelup/ts-jest, I pinned the jump in type checking duration to 0.7.0 -> 1.0.0.
For 0.7.0, the type checking still takes around 160ms. After installing 1.0.0 the same file takes 490ms. So something that was changed after 0.7.0 causes a massive regression in type-checking performance.
I did not investigate any further though, so I don't know what code changes may have causes the issue in particular. But if time allows it, I hope I can check your code and how it may be optimized.