Use Symbol for request properties

src/abort-controller.middleware.ts

@@ -1,6 +1,7 @@
 import { Injectable, NestMiddleware, Logger } from '@nestjs/common';
 import { Response } from 'express';
 import { AbortControllerOptions, AbortControllerRequest } from './types';
+import { ABORT_CONTROLLER, ABORT_SIGNAL } from './constants';
 
 const LOG_MESSAGES = {
   CLIENT_DISCONNECTED: 'Client disconnected, aborting request',
@@ -24,8 +25,8 @@ export class AbortControllerMiddleware implements NestMiddleware {
     const timeout = AbortControllerMiddleware.options.timeout ?? 30000;
     const enableLogging = AbortControllerMiddleware.options.enableLogging ?? false;
 
-    req.abortController = controller;
-    req.abortSignal = controller.signal;
+    req[ABORT_CONTROLLER] = controller;
+    req[ABORT_SIGNAL] = controller.signal;
 
     req.on('close', () => {
       if (enableLogging) {

src/abort-signal.decorator.ts

@@ -1,6 +1,7 @@
 import { createParamDecorator, ExecutionContext } from '@nestjs/common';
+import { ABORT_SIGNAL } from './constants';
 
 export const NestAbortSignal = createParamDecorator((_, ctx: ExecutionContext): AbortSignal => {
   const req = ctx.switchToHttp().getRequest();
-  return req.abortSignal;
+  return req[ABORT_SIGNAL];
 });

src/constants.ts

@@ -0,0 +1,2 @@
+export const ABORT_CONTROLLER = Symbol('abortController');
+export const ABORT_SIGNAL = Symbol('abortSignal');

src/index.ts

@@ -3,3 +3,4 @@ export * from './abort-signal.decorator';
 export * from './abort.module';
 export * from './types';
 export * from './throw-if-aborted';
+export * from './constants';

src/types.ts

@@ -1,8 +1,9 @@
 import { Request } from 'express';
+import { ABORT_CONTROLLER, ABORT_SIGNAL } from './constants';
 
 export interface AbortControllerRequest extends Request {
-  abortController?: AbortController;
-  abortSignal?: AbortSignal;
+  [ABORT_CONTROLLER]?: AbortController;
+  [ABORT_SIGNAL]?: AbortSignal;
 }
 
 export interface AbortControllerOptions {