Closed
Description
- Version: v16.4.0、v14.17.1
- Platform: Windows 10 x64
- Subsystem: child_process
What steps will reproduce the bug?
when using ES module and child_process to fork child process, even 'spawn' event has happend，child process failed receive message from parent process.
Complete Testcase
package.json:
{
"type": "module"
}master.js
import { join } from 'path'
import { fork } from 'child_process'
import { fileURLToPath } from 'url'
const __dirname = join(
fileURLToPath(import.meta.url),
'../'
)
const worker = fork(
join(__dirname, './worker.js')
);
worker.on('spawn', () => {
console.log('start success');
worker.send('hello', () => console.log('send success'));
});worker.js
console.log('child process has started, processID:', process.pid);
process.on('message', (msg) => {
console.log('child process get msg:', msg);
});console ouput:
start success
send success
child process has started, processID: 6224
if i delay 1s send message to child process, it works:
worker.on('spawn', () => {
console.log('start success');
setTimeout(() => {
worker.send('hello', () => console.log('send success'));
}, 1000);
});console output:
start success
child process has started, processID: 18156
send success
child process get msg: hello
What is the expected behavior?
the expected behavior just like this:
start success
send success
child process has started, processID: 16428
child process get msg: hello
when i rename worker.js to worker.cjs, got expected result.
Possible cause
I suspect this may have something to do with ESM asynchronous execution.