hookupjs

In larger projects, it's common to have multiple components that take varying amounts of time to start. It makes sense to start these components in parallel to ensure a fast and efficient application startup.

This project aims to make this as simple and fast as possible, while also offering some handy features that can be enabled—such as importing files without extensions or entire directories (via index.js lookup).

These features, along with importing other file types, are enabled using the new module.registerHook functionality in Node.js.

Zero dependencies and highly configurable.

import boot from 'hookupjs';

boot('./boot');

Table of Contents

Installation
Usage
App
Examples

Installation

npm i hookupjs

Usage

function boot(specifier: string, options?: BootOptions): Promise<App>

function boot(specifier: string, parentURL?: string, options?: BootOptions): Promise<App>

function boot(sequences: Sequences, options?: BootOptions): Promise<App>

specifier and parentURL

Option	Type	Description
specifier	string	Path to the boot module that exports the Sequences. The path is resolved relative to parentURL if specified or the current file if not.
parentURL?	string	Base url used to import the specifier. Must be a file URL string. Optional due to auto-detection. Startup is faster if this is specified. Example: import.meta.url.

boot('./boot/sequences.js', import.meta.url);

Sequences

Option	Type	Description
[key]	Function	Executed in parallel with other boot sequences. The return value is registered under the name (key) in the resulting App object returned by boot. App is also the first parameter passed to the function.

// boot/sequences.js
export { default as api } from './api.js';
export { default as db } from './db.js';
export { default as session } from './session.js';

// Exports something like this:
// { api: [AsyncFunction], db: [AsyncFunction], session: [AsyncFunction] }

// boot/db.js
import DatabaseClient from 'database';

export default async function db() {
	const client = new DatabaseClient();
	await client.connect();

	return client.getDb();
}

// boot/api.js
import http from 'node:http';

export default async function api() {
	const server = http.createServer((req, res) => {
		// Handle HTTP API calls
	});

	server.listen(3000);

	return server;
}

// boot/session.js
export default async function session(app) {
	const db = await app.db;

	const session = await db.getSession();
	return session;
}

BootOptions

Option	Type	Description
base	App	An optional base object to which each boot sequence will be attached.
global	boolean	If true, the App will be attached to the global scope (global.app).
registerLoaders	LoaderOptions	Custom loaders that enables different import types.
resolve	ResolveOptions	Options to customize how modules/resources are resolved.
imports	imports	Custom import map to resolve modules/resources.
beforeLoading	(app) => void	Hook called before loading the sequences.
imported	(sequences) => sequences | void	Hook called after the sequences got imported. Return value overrides the sequences if something other then undefined is returned
wrapper	(run) => app | void	If you need to wrap the sequences run logic you can use this wrapper hook. The return value of this wrapper function is also the return value of boot
initialized	(app) => void	Hook called after the sequences have initialized.
booted	(app) => void	Hook called after the app is fully booted.
onError	(key, error) => void	Hook called if any error occurs during boot.

LoaderOptions

// Import type json works by default
import pkg from './package.json' with { type: 'json' };

// Enable other types for import
import emailTemplate from './resources/email-template.html' with { type: 'text' };
import logo from './resources/logo.png' with { type: 'buffer' };

Option	Type	Description
text	true Function	Enables import with type text. Use a function for custom implementation.
buffer	true Function	Enables import with type buffer. Use a function for custom implementation (source is not available).
[key]	Function	Use custom functions to enable import with custom types.

Function definition: (source: Buffer, url: string) => string

// ...
const registerLoaders = {
	text: true,
	yaml: (source) => `export default ${yaml.parse(source.toString())}`,
	json5: (source) => `export default ${JSON5.parse(source.toString())}`,
	properties: (source) => `export default ${properties.parse(source.toString())}`,
	toml: (source) => `export default ${toml.parse(source.toString())}`,
	xml: (source) => `export default ${xml2js(source.toString())}`,
	// ...
};
// ...

ResolveOptions

// Import directories (auto-resolve index file)
import { SpecialService } from './services';

// Import modules without extensions (auto-resolve extensions)
import model from './model';
import controller from './controller';

// Enable search string forwarding (logger module can read the query params via import.meta.url)
import childLogger from 'logger?child=db';

Option	Type	Description
directories	true	Enables importing directories (specifically, imports the index file from the directory).
extensions	true string[]	Enables importing without extensions. Provide an array of strings defining which extensions to auto-complete.
handleSearch	true	Enables forwarding of the search string (or query string). Can be accessed via import.meta.url in the imported module.

// ...
const resolve = {
	directories: true,
	extensions: ['.js', '.mjs', '.cjs'],
	handleSearch: true,
}
// ...

imports

Define a map that applies to import specifiers.

imports = {
	'logger': 'some-logger-package', // Direct replacement
	'logger': './src/logger', // Relative paths getting resolved relative to `parentURL` if specified or the current file if not
	'logger': import.meta.resolve('./src/logger'), // Absolute paths needs to be file urls (file://)
	'~/utils/*': './src/utils/*', // A wildcard (*) can be used to match any number of characters and forward them to the replacement
	'#/*': './src/*', // If a wildcard (*) is used, both sides needs the wildcard. Only one wildcard is allowed
	'#/boot': './src/start.js', // '#/boot' will never getting matched. The wildcard in '#/*' above consumes 'boot'. Needs to be defined before any wildcard
	'@services/*': './src/services/*.service.js', // Resolves '@services/email' to 'file://path/to/src/services/email.service.js'
}

App

The returned promises by the sequence functions are registered under there respective names into the App. Use await on these promises where you need the actual value. There are two ways to access the App everywhere in the project.

import app from 'hookupjs/app';
// or
global.app // if global is set to true in the options

// This function getting called by an incoming http request
export async function uploadImage(userId, imageBuffer) {
	// Image upload logic here
	// ...

	const db = await app.db;
	db.save('image', { uuid, userId, imageUrl });

	const sockets = await app.sockets;
	sockets.sendMessage(userId, 'image uploaded');
}

// or e. g. services/db.js
export async function query(query, params) {
	const db = await app.db;
	const result = await db.query(query, params);
	logger.verbose(query, params, result);
	return result;
}

// or e. g. services/queue.js
export async function handleMessage(uuid, payload) {
	// handle logic here
	// ...

	const queue = await app.queue;
	queue.ack(uuid, result);
}

Examples

Check the examples folder for more ideas.

// main.js
import { EventEmitter } from 'node:events';
import logger from 'logger';
import boot from 'hookupjs';

const app = await boot('./boot', {
	base: new EventEmitter(),
	global: true, // global.app = base
	registerLoaders: {
		text: true,
	},
	resolve: {
		directories: true,
	},
	initialized: app => app.emit('app.initialized'),
	booted: (app) => {
		app.emit('app.boot.complete');
	},
	onError: (key, error) => {
		logger.fatal(`Error during boot sequence "${key}"!`, error);
	},
});

// global.app === app && app instanceof EventEmitter
app.emit('app.boot.complete.too');

// boot.js
export async function queue(app) {
	// global.app === app
	const db = await app.db;
	const queueRaw = db.getAll('queue');
	const queue = await QueueService.init(queueRaw);

	return queue;
}

export async function db() {
	const connection = await DatabaseClient.connect();
	const db = connection.getDb();

	return db;
}