@openreachtech/mentsu-process-clerk

A small clerk class that manages Node.js process event listeners (sinks) and provides convenient process-exit helpers.

Overview

ProcessClerk wraps a Node.js process object and offers two things:

• Attaching and detaching a sink — a plain object that maps process event names (e.g. SIGINT, SIGTERM) to their listener functions — in one call.
• Exiting the process with well-known exit codes through readable helper methods.

By taking the process object as a constructor parameter, the clerk stays easy to test: a mock process can be injected instead of the real one.

Installation

Requires Node.js 20.x (the version the CI builds against).

npm install @openreachtech/mentsu-process-clerk

It is an ES module ("type": "module"); import it with ESM import syntax.

Usage

Create a clerk, attach a sink of process event listeners, and exit gracefully when a signal arrives.

import { ProcessClerk } from '@openreachtech/mentsu-process-clerk'

const alphaClerk = ProcessClerk.create()

const alphaSink = {
  SIGINT: () => {
    console.log('Received SIGINT, shutting down...')

    alphaClerk.exitBySigint()
  },
}

// Attach the listeners to the process.
alphaClerk.attachSink({
  sink: alphaSink,
})

// Later, detach them when they are no longer needed.
alphaClerk.detachSink({
  sink: alphaSink,
})

API

Class members are written with the following notation.

| notation | members | | :-- | :-- | | #instanceProperty | instance property | | #instanceMethod() | instance method | | #get:instanceGetter | instance getter | | #set:instanceSetter | instance setter | | .staticProperty | static property | | .staticMethod() | static method | | .get:staticGetter | static getter | | .set:staticSetter | static setter |

ProcessClerk

Clerk to manage process event sinks.

.create()

Factory method. Creates a new instance.

.create({ rawProcess? }?) => ProcessClerk

| parameter | type | description | | :-- | :-- | :-- | | rawProcess | NodeJS.Process | The process object to manage. Optional. Defaults to the global process. |

#attachSink()

Attaches a sink to the process. Each entry of the sink is registered with process.on(eventName, listener).

#attachSink({ sink? }) => NodeJS.Process | null

| parameter | type | description | | :-- | :-- | :-- | | sink | Record<string, (...args: Array<*>) => void> \| null | Map of event names to listener functions. Optional. Defaults to null. |

Returns the process with the listeners attached, or null when the sink is invalid (not an object, or containing a value that is not a function).

#detachSink()

Detaches a sink from the process. Each entry of the sink is removed with process.off(eventName, listener).

#detachSink({ sink? }) => NodeJS.Process | null

| parameter | type | description | | :-- | :-- | :-- | | sink | Record<string, (...args: Array<*>) => void> \| null | Map of event names to listener functions. Optional. Defaults to null. |

Returns the process with the listeners detached, or null when the sink is invalid.

#exitAsSuccess()

Exits the process as success (exit code 0).

#exitAsSuccess() => void

#exitAsFailure()

Exits the process as failure (exit code 1).

#exitAsFailure() => void

#exitAsMisuse()

Exits the process as misuse (exit code 2).

#exitAsMisuse() => void

#exitBySigint()

Exits the process by SIGINT (exit code 130).

#exitBySigint() => void

#exit()

Exits the process with the given exit code.

#exit({ exitCode? }?) => void

| parameter | type | description | | :-- | :-- | :-- | | exitCode | number | The exit code passed to process.exit(). Optional. Defaults to 0. |

Contribution

Bug reports, feature requests, and code contributions are welcome.

Feel free to contact us through GitHub Issues.

git clone https://github.com/openreachtech/mentsu-process-clerk.git
cd mentsu-process-clerk
npm install
npm run lint
npm test

License

This project is released under the Apache License 2.0.

For more details, please see in the LICENSE file.

Developer

Open Reach Tech Inc.

Copyright

© 2026 Open Reach Tech Inc.