Architecture

Aspect-Oriented Programming

Cross-cutting concerns made easy. Use Interceptors, Guards, and Pipes to decouple logic from your business code.

Interceptors

Intercept/transform requests and responses.

Guards

Determine if a request should be handled.

Pipes

Validate and transform input data.

Interceptors

Inspired by NestJS, interceptors allow you to wrap the execution stream. Perfect for logging, transformation, or caching.

logging.interceptor.ts

1import { createInterceptor, UseInterceptors } from "canxjs";
2
3// Define an Interceptor
4const LoggingInterceptor = createInterceptor(async (context, next) => {
5  console.log('Before...');
6  const now = Date.now();
7  
8  const result = await next();
9  
10  console.log(`After... ${Date.now() - now}ms`);
11  return result;
12});
13
14// Apply to Controller or Method
15@UseInterceptors(LoggingInterceptor)
16class CatsController {
17  // ...
18}

Guards

auth.guard.ts

1import { createGuard, UseGuards } from "canxjs";
2
3const AuthGuard = createGuard((context) => {
4  const req = context.getRequest();
5  return validateRequest(req);
6});
7
8@UseGuards(AuthGuard)
9class protectedController {}

Pipes

validation.pipe.ts

1import { ParseIntPipe, UsePipes } from "canxjs";
2
3@Post()
4@UsePipes(ParseIntPipe) // Transforms params automatically
5create(@Body() createCatDto: CreateCatDto) {
6  // ...
7}

Next Steps

Explore the validation system.