10 Cutting Angular cross-cuts.md

Cutting Angular cross-cuts

Links

• slides: https://speakerdeck.com/mgechev/cutting-angulars-crosscuts
• aspect.js https://github.com/mgechev/aspect.js

SOLID

• Single responsibility principle (SRP)
• Open closed principle (OCP)
• Liskov substitution principle (LSP)
• Interface segregation principle (ISP)
• Dependency injection principle (DIP)

Caching

Caching crosscut levels of abstractions. Caching is a cross-cutting concern

These must be separated: caching, logging, ..

Caching aspect example

èxport class CacheAspect {
    beforeUserFinderGetInvocation(meta, id) {
        this.queryCache(lsCache, meta.method, id);
    }

    afterUserFinderGetInvocation(meta,id){
        this.setCache(lsCache, meta.method, id);
    }

    // same for Http
}

Using an aspect

AspectJS library: aspect.js

@Wove()
export class Http {
    get(url: string){
        ...
    }
}

export class CacheAspect {
    @before(/.*/, /^get)
    before(m, param) { ... }

    @after(/.*/, /^get/)
    after(m, id) { ... }
}