chore: export extractProperties (#76)

.changeset/tasty-maps-smoke.md

@@ -0,0 +1,5 @@
+---
+"synckit": patch
+---
+
+chore: export extractProperties

package.json

@@ -105,7 +105,7 @@
     ]
   },
   "typeCoverage": {
-    "atLeast": 99.5,
+    "atLeast": 99.67,
     "cache": true,
     "detail": true,
     "ignoreAsAssertion": true,

src/index.ts

@@ -48,31 +48,14 @@ export interface SynckitOptions {
 // MessagePort doesn't copy the properties of Error objects. We still want
 // error objects to have extra properties such as "warnings" so implement the
 // property copying manually.
-const extractProperties = (object: unknown): Record<string, unknown> => {
-  const properties: Record<string, unknown> = {}
+export const extractProperties = <T>(object?: T): T | undefined => {
   if (object && typeof object === 'object') {
+    const properties = {} as T
     for (const key in object) {
-      properties[key] = (object as Record<string, unknown>)[key]
+      properties[key as keyof T] = object[key]
     }
+    return properties
   }
-  return properties
-}
-
-// MessagePort doesn't copy the properties of Error objects. We still want
-// error objects to have extra properties such as "warnings" so implement the
-// property copying manually.
-const applyProperties = <T>(
-  object: T,
-  properties?: Record<string, unknown>,
-): T => {
-  if (!properties) {
-    return object
-  }
-  // eslint-disable-next-line sonar/for-in
-  for (const key in properties) {
-    ;(object as Record<string, unknown>)[key] = properties[key]
-  }
-  return object
 }
 
 export function createSyncFn<T extends AnyAsyncFn>(
@@ -166,15 +149,16 @@ function startWorkerThread<R, T extends AnyAsyncFn<R>>(
       result,
       error,
       properties,
-    } = receiveMessageOnPort(mainPort)!.message as WorkerToMainMessage<R>
+    } = (receiveMessageOnPort(mainPort) as { message: WorkerToMainMessage<R> })
+      .message
 
     /* istanbul ignore if */
     if (id !== id2) {
       throw new Error(`Internal error: Expected id ${id} but got id ${id2}`)
     }
 
     if (error) {
-      throw applyProperties(error, properties)
+      throw Object.assign(error, properties)
     }
 
     return result!

src/types.ts

@@ -32,7 +32,7 @@ export interface WorkerData {
 export interface DataMessage<T> {
   result?: T
   error?: unknown
-  properties?: Record<string, unknown>
+  properties?: unknown
 }
 
 export interface WorkerToMainMessage<T = unknown> extends DataMessage<T> {

test/fn.spec.ts

@@ -2,12 +2,13 @@ import { createRequire } from 'module'
 
 import { jest } from '@jest/globals'
 
-import { createSyncFn } from 'synckit'
+import { createSyncFn, extractProperties } from 'synckit'
 
 type AsyncWorkerFn<T = number> = (result: T, timeout?: number) => Promise<T>
 
 beforeEach(() => {
   jest.resetModules()
+
   delete process.env.SYNCKIT_BUFFER_SIZE
   delete process.env.SYNCKIT_TIMEOUT
 
@@ -45,7 +46,7 @@ test('createSyncFn', () => {
   expect(syncFn3(2)).toBe(2)
   expect(syncFn3(5, 0)).toBe(5)
 
-  expect(() => errSyncFn()).toThrow('Worker Error')
+  expect(() => errSyncFn()).toThrowErrorMatchingInlineSnapshot(`"Worker Error"`)
 
   const syncFn4 = createSyncFn<AsyncWorkerFn>(workerCjsPath)
 
@@ -66,3 +67,18 @@ test('timeout', async () => {
     'Internal error: Atomics.wait() failed: timed-out',
   )
 })
+
+test('extractProperties', () => {
+  expect(extractProperties()).toBeUndefined()
+  expect(extractProperties({})).toEqual({})
+  expect(extractProperties(new Error('message'))).toEqual({})
+  expect(
+    extractProperties(
+      Object.assign(new Error('message'), {
+        code: 'CODE',
+      }),
+    ),
+  ).toEqual({
+    code: 'CODE',
+  })
+})