Refactor (packages/llm/src/schema/options.ts): Function with high complexity

.devcontainer/devcontainer-lock.json

@@ -0,0 +1,9 @@
+{
+  "features": {
+    "ghcr.io/devcontainers-extra/features/bun:1": {
+      "version": "1.1.0",
+      "resolved": "ghcr.io/devcontainers-extra/features/bun@sha256:0624284ecaead9dd4c6654616a7f939cfa4ebcbc60593700a74e35b1767befa5",
+      "integrity": "sha256:0624284ecaead9dd4c6654616a7f939cfa4ebcbc60593700a74e35b1767befa5"
+    }
+  }
+}

.devcontainer/devcontainer.json

@@ -0,0 +1,25 @@
+// For format details, see https://aka.ms/devcontainer.json. For config options, see the
+// README at: https://github.com/devcontainers/templates/tree/main/src/typescript-node
+{
+	"name": "Node.js & TypeScript",
+	// Or use a Dockerfile or Docker Compose file. More info: https://containers.dev/guide/dockerfile
+	"image": "mcr.microsoft.com/devcontainers/typescript-node:5-24-trixie",
+	"features": {
+		"ghcr.io/devcontainers-extra/features/bun:1": {}
+	}
+
+	// Features to add to the dev container. More info: https://containers.dev/features.
+	// "features": {},
+
+	// Use 'forwardPorts' to make a list of ports inside the container available locally.
+	// "forwardPorts": [],
+
+	// Use 'postCreateCommand' to run commands after the container is created.
+	// "postCreateCommand": "yarn install",
+
+	// Configure tool-specific properties.
+	// "customizations": {},
+
+	// Uncomment to connect as root instead. More info: https://aka.ms/dev-containers-non-root.
+	// "remoteUser": "root"
+}

.github/workflows/test.yml

@@ -63,6 +63,10 @@ jobs:
         # vCPUs across 5 packages' test tasks running at once — same
         # contention issue typecheck.yml already caps for tsgo.
         run: GITHUB_ACTIONS=false bun turbo test --concurrency=4
+
+      - name: Run mergeJsonRecords tests
+        working-directory: packages/llm
+        run: bun test test/schema.test.ts
 
       - name: Check generated client
         timeout-minutes: 5

packages/llm/src/schema/options.ts

@@ -3,19 +3,46 @@ import { JsonSchema, ModelID, ProviderID } from "./ids"
 import type { AnyRoute } from "../route/client"
 import { isRecord } from "../utils/record"
 
-export const mergeJsonRecords = (
+const mergeJsonRecordValue = (current: unknown, next: unknown): unknown => {
+  if (isRecord(current) && isRecord(next)){
+    return mergeJsonRecords(current, next)
+  }
+
+  return next
+}
+
+const mergeJsonRecordInto = (
+  result: Record<string, unknown>,
+  item: Record<string, unknown>,
+):void =>  {
+  for (const [key, value] of Object.entries(item)){
+    if (value === undefined) continue
+    result[key] = mergeJsonRecordValue(result[key], value)
+  }
+}
+
+
+export const  mergeJsonRecords = (
   ...items: ReadonlyArray<Record<string, unknown> | undefined>
 ): Record<string, unknown> | undefined => {
-  const defined = items.filter((item): item is Record<string, unknown> => item !== undefined)
+  const defined = items.filter(
+    (item): item is Record<string, unknown> => item !== undefined,
+  )
+
   if (defined.length === 0) return undefined
-  if (defined.length === 1 && Object.values(defined[0]).every((value) => value !== undefined)) return defined[0]
+
+  if (defined.length === 1 && 
+      Object.values(defined[0]).every((value) => value !== undefined)
+    ) {
+        return defined[0]
+    }
+
   const result: Record<string, unknown> = {}
+
   for (const item of defined) {
-    for (const [key, value] of Object.entries(item)) {
-      if (value === undefined) continue
-      result[key] = isRecord(result[key]) && isRecord(value) ? mergeJsonRecords(result[key], value) : value
-    }
+    mergeJsonRecordInto(result, item)
   }
+
   return Object.keys(result).length === 0 ? undefined : result
 }
 

packages/llm/test/schema.test.ts

@@ -2,7 +2,7 @@ import { describe, expect, test } from "bun:test"
 import { Schema } from "effect"
 import * as OpenAIChat from "../src/protocols/openai-chat"
 import * as OpenAIResponses from "../src/protocols/openai-responses"
-import { ContentPart, LLMEvent, LLMRequest, Model, ModelID, ProviderID, Usage } from "../src/schema"
+import { ContentPart, LLMEvent, LLMRequest, Model, ModelID, ProviderID, Usage, mergeJsonRecords} from "../src/schema"
 import { ProviderShared } from "../src/protocols/shared"
 
 const model = new Model({
@@ -58,6 +58,39 @@ describe("llm schema", () => {
   })
 })
 
+
+describe("mergeJsonRecords", () =>{
+  test("returns undefined when all inputs are undefined", () => {
+    expect(mergeJsonRecords(undefined, undefined)).toBeUndefined()
+  })
+
+  test("returns a single defined record unchanged", ()=>{
+    const input = {a:1, b: "test"}
+
+    expect(mergeJsonRecords(input)).toBe(input)
+  })
+
+  test("recursively merges nested records", () => {
+    expect(
+      mergeJsonRecords(
+        { config: { a: 1 } },
+        { config: { b: 2 } },
+      ),
+    ).toEqual({
+      config: {
+        a: 1,
+        b: 2,
+      },
+    })
+  })
+
+  test("ignores undefined values when merging", () => {
+    expect(mergeJsonRecords({ a: 1 }, { a: undefined })).toEqual({
+      a: 1,
+    })
+  })
+})
+
 describe("LLM.Usage", () => {
   test("subtractTokens clamps non-sensical breakdowns to zero", () => {
     // Defense against a provider reporting cached_tokens > prompt_tokens or