server-hooks

This library provides very simple way to work with dependencies in your server code

The main point of this library is to provide small abstraction on top of node's AsyncLocalStorage API to define scopes inside your async code. Unlike most of DI solutions it doesn't require you to use decorators or DI instance directly.

Installation

npm install -S server-hooks

Usage example

Imagine that you have a logger and you would like to write messages with requestId value which you are could receive only in your http request handler. And you would like to use it like so

export function myFancyLogic(fancyArg: Fancy) {
    const logger = useLogger();
    // Do some staff
    logger.debug('Fancy work is done');
}

First of all we should define our logger context definition

import {createContext, useContext, withContext} from "server-hooks";
import {logger} from './your-logger';

// Give a name for the context and 
// let's use current logger as an initial value
const LoggerCtx = createContext("logger", logger);

// Define specified function to define context value
export function withLogger(data: object) {
    withContext(LoggerCtx, (current) => current.child(data))
}

// And just create shorhand hook 
// to easily use it inside your code
export function useLogger() {
    return useContext(LoggerCtx);
}

Now let's imagine that we have some framework to deal with http requests and all that you need is to call two functions.

import {dispatch} from "server-hooks";
import {withLogger} from '../services/logger'

function handler(request: Request) {
    return dispatch(async () => {
        withLogger({requestId: request.headers['x-request-id']});
        return await router.execute(request);
    });
}

Development

This project uses bun by default.

# Run tests
bun test
# Generate dist output
bun run build