util: process signal to exit code utility

[ErickWendel]

Description

Adds util.convertProcessSignalToExitCode() utility function to convert signal names (e.g., SIGTERM, SIGKILL) to their corresponding POSIX exit codes.

When a child process is terminated by a signal, the code parameter in the 'exit' and 'close' events is null. This utility allows users to convert the signal parameter to the POSIX standard exit code.

Example

import { spawn } from 'node:child_process';
import { once } from 'node:events';
import { convertProcessSignalToExitCode } from 'node:util';

const ls = spawn('ls', ['-lh', '/usr']);

ls.kill();

const [code, signal] = await once(ls, 'exit');
const exitCode = convertProcessSignalToExitCode(signal);
console.log(`signal ${signal}, POSIX exit code: ${exitCode}`);

// signal SIGTERM, POSIX exit code: 143

Note: While Windows doesn't natively support POSIX signals, Node.js provides a cross-platform abstraction that emulates signal behavior. This allows convertProcessSignalToExitCode() to work consistently across all platforms, returning the same POSIX exit codes on both Unix-like systems and Windows.

Refs

• child_process.exitCode is null after process exited #60285
• child_process: set exitCode when process is killed by signal #60720

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.54%. Comparing base (cbe0233) to head (ccf99c9).
⚠️ Report is 16 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #60963      +/-   ##
==========================================
+ Coverage   88.53%   88.54%   +0.01%     
==========================================
  Files         703      703              
  Lines      208413   208448      +35     
  Branches    40191    40195       +4     
==========================================
+ Hits       184521   184575      +54     
+ Misses      15902    15884      -18     
+ Partials     7990     7989       -1     

Files with missing lines	Coverage Δ
lib/internal/util.js	96.81% <100.00%> (+0.43%)	⬆️
lib/util.js	97.97% <100.00%> (+<0.01%)	⬆️

... and 43 files with indirect coverage changes

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[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/70458/

[aduh95]

Seemingly related failure on Windows:

---
duration_ms: 175.001
exitcode: 1
severity: fail
stack: |-
  node:internal/modules/run_main:107
      triggerUncaughtException(
      ^

  AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:

  150 !== 134

      at file:///c:/workspace/node-test-binary-windows-js-suites/node/test/parallel/test-util-convert-signal-to-exit-code.mjs:20:10
      at ModuleJob.run (node:internal/modules/esm/module_job:430:25)
      at async onImport.tracePromise.__proto__ (node:internal/modules/esm/loader:654:26)
      at async asyncRunEntryPointWithESMLoader (node:internal/modules/run_main:101:5) {
    generatedMessage: true,
    code: 'ERR_ASSERTION',
    actual: 150,
    expected: 134,
    operator: 'strictEqual',
    diff: 'simple'
  }

  Node.js v26.0.0-pre

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/70463/