async-context

Lets your async functions have local context, accessible from within any call inside them.

Example 1

Wrap your async functions in the AsyncContext.run function:

``js
function someInnerFunction() {
console.log(AsyncContext.get("myGlobalData"));
//{message: "hello"}
}
function yourAsyncFunction() {
AsyncContext.set("myGlobalData", {message: "hello"});
someInnerFunction();
}

AsyncContext.run(yourAsyncFunction, [], yourData);
`

Example 2

ContextSetter can be used to provide multiple functions that set different contexts:

`js
const yourSetters = [
(data) => {
AsyncContext.set("requestId", uuid())
},
(data) => {
AsyncContext.set("someOtherGlobalData", {})
},
]
AsyncContext.run(yourAsyncFunction, yourSetters, yourData);
`

Example 3 (NestJS)

NestJS Middleware can be used to intercept requests and add context to them which then can be accessed from any subsequent layer:

`js

function contextMiddleware(req: Request, res: Response, next: NextFunction) {
const yourSetters = [
(req) => {
AsyncContext.set("requestId", uuid())
},
(req) => {
AsyncContext.set("someOtherGlobalData", {})
},
];
AsyncContext.run(next, yourSetters, req);
};

export class AppModule implements NestModule {
configure(consumer: MiddlewareConsumer) {
consumer
.apply(contextMiddleware)
.forRoutes({ path: 'example', method: RequestMethod.GET });
}
}

//example.controller.ts

@Get('example')
async getExamples() {
console.log(AsyncContext.get("requestId"));
//outputs some uuid
}
``