tests: add benchmarking for type inference complexity

package.json

@@ -49,7 +49,10 @@
     "type-check:test": "tsc --noEmit --project tsconfig.test.json",
     "db:clean": "cd test/db && docker compose down --volumes",
     "db:run": "cd test/db && docker compose up --detach && wait-for-localhost 3000",
-    "db:generate-test-types": "cd test/db && docker compose up --detach && wait-for-localhost 8080 && curl --location 'http://0.0.0.0:8080/generators/typescript?included_schemas=public,personal&detect_one_to_one_relationships=true' > ../types.generated.ts && node ../scripts/update-json-type.js && prettier --write ../types.generated.ts"
+    "db:generate-test-types": "cd test/db && docker compose up --detach && wait-for-localhost 8080 && curl --location 'http://0.0.0.0:8080/generators/typescript?included_schemas=public,personal&detect_one_to_one_relationships=true' > ../types.generated.ts && node ../scripts/update-json-type.js && prettier --write ../types.generated.ts",
+    "benchmark:types": "tsx test/types-benchmark/benchmarks.ts",
+    "benchmark:update-baselines": "node test/types-benchmark/update-baselines.js --update",
+    "benchmark:show-baselines": "node test/types-benchmark/update-baselines.js --show"
   },
   "dependencies": {
     "@supabase/node-fetch": "^2.6.14"
@@ -66,6 +69,7 @@
     "semantic-release-plugin-update-version-in-files": "^1.1.0",
     "ts-jest": "^28.0.3",
     "tstyche": "^4.3.0",
+    "tsx": "^4.20.5",
     "type-fest": "^4.32.0",
     "typedoc": "^0.22.16",
     "typescript": "^4.5.5",

test/attest-test.ts

@@ -0,0 +1 @@
+

test/types-benchmark/README.md

@@ -0,0 +1,47 @@
+# PostgREST-js Type Inference Benchmarks
+
+Type inference performance benchmarks using [@ark/attest](https://github.com/arktypeio/arktype/tree/main/ark/attest) based on the approach from [An approach to optimizing TypeScript type checking performance](https://www.geldata.com/blog/an-approach-to-optimizing-typescript-type-checking-performance).
+
+## Quick Start
+
+```bash
+# Run benchmarks and see performance vs baseline
+npm run benchmark:types
+
+# Update baselines (like vitest --update)
+npm run benchmark:update-baselines
+
+# Show current baselines
+npm run benchmark:show-baselines
+```
+
+## Files
+
+- **`benchmarks.ts`** - Core PostgREST operations (select, update, insert, RPC)
+- **`baselines.json`** - Current baseline values for all benchmarks
+- **`update-baselines.js`** - Baseline management utility
+- **`tsconfig.json`** - TypeScript configuration for benchmarks
+
+## Understanding Results
+
+- **📊 Delta: 0.00%** - Performance is stable (no change)
+- **📈 Exceeded baseline by X%** - Performance degraded (more instantiations)
+- **📉 Under baseline by X%** - Performance improved (fewer instantiations)
+
+## Updating Baselines
+
+When you make intentional changes that affect type inference performance:
+
+```bash
+npm run benchmark:update-baselines
+```
+
+This captures current performance as the new baseline, similar to `vitest --update` for snapshots.
+
+## Current Baseline Values
+
+- **Simple Select: Basic**: 1,935 instantiations
+- **Simple Select: Single Column**: 3,044 instantiations
+- **Simple Update: Basic**: 108 instantiations
+- **Simple Insert: Basic**: 108 instantiations
+- **Simple RPC: Basic**: 53 instantiations

test/types-benchmark/baselines.json

@@ -0,0 +1,7 @@
+{
+  "Simple Select: Basic": 1935,
+  "Simple Select: Single Column": 3044,
+  "Simple Update: Basic": 108,
+  "Simple Insert: Basic": 108,
+  "Simple RPC: Basic": 53
+}

test/types-benchmark/benchmarks.ts

@@ -0,0 +1,29 @@
+import { bench } from '@ark/attest'
+import { PostgrestClient } from '../../src/index'
+import { Database } from '../types.generated'
+
+// Create a mock client for type inference testing
+const createMockClient = () => {
+  return new PostgrestClient<Database>('http://localhost:3000')
+}
+
+// Simple benchmarks that should work
+bench('Simple Select: Basic', () => {
+  return createMockClient().from('users').select()
+}).types([1935, 'instantiations'])
+
+bench('Simple Select: Single Column', () => {
+  return createMockClient().from('users').select('username')
+}).types([3044, 'instantiations'])
+
+bench('Simple Update: Basic', () => {
+  return createMockClient().from('users').update({ status: 'ONLINE' })
+}).types([108, 'instantiations'])
+
+bench('Simple Insert: Basic', () => {
+  return createMockClient().from('users').insert({ username: 'testuser' })
+}).types([108, 'instantiations'])
+
+bench('Simple RPC: Basic', () => {
+  return createMockClient().rpc('get_status', { name_param: 'test' })
+}).types([53, 'instantiations'])