-import { isPlainObject } from '../utils'
-import type { TaskFunction } from './task-functions'
-import { KillBehaviors, type WorkerOptions } from './worker-options'
+import { isPlainObject } from '../utils.js'
+import type { TaskFunction } from './task-functions.js'
+import { KillBehaviors, type WorkerOptions } from './worker-options.js'
-export const checkValidWorkerOptions = (opts: WorkerOptions): void => {
+export const checkValidWorkerOptions = (
+ opts: WorkerOptions | undefined
+): void => {
if (opts != null && !isPlainObject(opts)) {
throw new TypeError('opts worker options parameter is not a plain object')
}