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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Know when a process ended due to the `child_process.spawn()` `timeout` option ","articleBody":"### What is the problem this feature will solve?\r\n\r\nWhen a process ends due to the `timeout` option of `child_process.spawn()`, there is no way to know whether that termination was due to the timeout. A `SIGTERM` is sent to the process, but that's pretty much it.\r\n\r\n```js\r\nimport {spawn} from 'node:child_process'\r\n\r\nconst childProcess = spawn('node', ['-e', 'setTimeout(() => {}, 1e7)'], {\r\n  timeout: 2e3, \r\n  stdio: 'inherit', // no stdout/stderr\r\n})\r\nchildProcess.on('exit', (exitCode, signal) => {\r\n  console.log({exitCode, signal}) // { exitCode: null, signal: 'SIGTERM' }\r\n})\r\n```\r\n\r\nThis makes debugging harder. Some users might be left wondering why the process ended if they don't pay attention to the `timeout` option.\r\n\r\n### What is the feature you are proposing to solve the problem?\r\n\r\nHaving a way to know whether the process ended due to the `timeout` option. Any implementation would work. Some potential ideas:\r\n  - `timeout` event on `childProcess`\r\n  - third boolean argument `timedOut` passed to the `exit` event\r\n  - emit an `error` event with `error.code: 'ETIMEDOUT'` on `childProcess`. This is a breaking change since many users are currently listening for `error` events, so would probably not be a good idea.\r\n  - `childProcess.timedOut = true`\r\n  - `childProcess.timedOut()` returning a boolean\r\n\r\n### What alternatives have you considered?\r\n\r\nOne could possibly set a manual timeout like the following.\r\n\r\n```js\r\nlet timedOut = false\r\nsetTimeout(() => {\r\n  timedOut = true\r\n}, 2e3)\r\n```\r\n\r\nHowever, it defeats some of the convenience of the `timeout` option, since that one might as well call `childProcess.kill()` themselves then. Also, it is slightly unreliable since an unrelated `SIGTERM` could theoretically have been sent at the exact same time.","author":{"url":"https://github.com/ehmicky","@type":"Person","name":"ehmicky"},"datePublished":"2024-01-24T21:05:48Z","url":"https://github.com/nodejs/node/issues/51561"}