export 'IMetadata' was not found in 'kaop-ts' about kaop-ts HOT 13 CLOSED

Hey there,

Firstly, appreciate your prompt response!

The Logging aspect works as expected. My IDE shows no errors either, however, in the browser is where i see the error.

Here is the full implementation (without @Injectable :)) -

import { AdvicePool, adviceMetadata, IMetadata } from 'kaop-ts'

export class LoggingAspect extends AdvicePool {
    static log( @adviceMetadata meta: IMetadata) {
        console.log('Called: ', meta.target)
        console.log('Args: ', meta.args)
    }
}

And the service method i am injecting it to is:

import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable'

// kaop imports
import { beforeMethod } from 'kaop-ts';
import { LogAspect } from '../sample-advice';

import 'rxjs/add/operator/toPromise';

@Injectable
export class MyService {

    constructor(private http: Http) { }

    @beforeMethod(LoggingAspect.log)
    httpGetRequest(url: string): Promise<Response> {
        return this.http.get(url)
            .toPromise().then(...)
    }
}

I also tried the example on the readme, with the same error in the browser console:

    static log( @adviceMetadata metadata: IMetadata) {
        console.log(`${metadata.target.name}::${metadata.propertyKey}()`) // class and method name
        console.log(`called with arguments: `)
        console.log(metadata.args) // function arguments
        console.log(`output a result of: `)
        console.log(metadata.result) // returned value
    }

(edit .. place ```javascript before a block of code to highlight :))

from kaop-ts.

Hi @musti2!

in the browser is where i see the error

How are you running it? Can you provide the exact steps in order to reproduce it? That'd help a lot

from kaop-ts.

@musti2 @k1r0s I found the issue, we can fix by changing IMetadata to an empty class, instead of an interface.

The problem is in TypeScript + Webpack side, not in ours, but apparently it's a real issue. When exporting code + interfaces in the same file, Webpack treats it as CJS modules instead of ESM, causing compile-time code (interfaces) to be looked up. Of course this is removed after all by TypeScript, so that's why it's a warning and things keep running.

There are 2 solutions: either split exports in separate files (one for code and another for interfaces) or rewrite the exported interfaces (IMetadata) as an empty class. Keep in mind empty classes, used as types (no new invoked) in TypeScript are removed when compiled, just as interfaces, so no junk code is generated.

More info on angular/angular-cli#2034 (comment)

from kaop-ts.

@k1r0s I think it was too early to close, since we didn't provide a final solution.

I've been investigating. As you could have seen in angular/angular-cli#2034 (comment), the issue have implications on Webpack, TypeScript and Angular, so prob the issue will remain for a time, and is not in our side. Is not too important anyway since is a warning.

Anyway, I've tried several things from kaop-ts side, and there is nothing we can do. The best workaround I found is in the angular app re-exporting the interface from an inteface-only file (very important, don't mix interfaces with variables, const, classes or functions in that file):

// app/interfaces.ts
...
export { IMetadata } from 'kaop-ts';
...

// app/logging-aspect.ts

import { adviceMetadata, AdvicePool } from 'kaop-ts'
import { IMetadata } from './interfaces' // Import from here instead

class LoggingAspect extends AdvicePool {
    static log( @adviceMetadata meta: IMetadata) {
        console.log('Called: ', meta.target);
        console.log('Args: ', meta.args);
    }
}

That will remove the warnings.

@k1r0s I'd suggest to add this case to a Troubleshooting section in the Readme. Then is more visible for the angular users

from kaop-ts.

Thanks to @musti2! We learnt something new today

from kaop-ts.

I think you're trying to inject an instance of LogAspect somewhere. You should import LogAspect and use LogAspect.log directly placing it on any decorator this lib provides.

log method is 'static' so there is no need to apply 'Injectable()' :)

by the way can you please provide a gist or paste your implementation?

from kaop-ts.

export 'IMetadata' was not found in 'kaop-ts' error is due Angular is trying to inject meta as an instance of IMetadata which is not declared as a dependency.

to retrieve method metadata you don't need @Injectable()

from kaop-ts.

So, advice is working but u got an error anyway? :\ seems weird

Hold on, I'm gonna test this

from kaop-ts.

I think Angular nor this library is the cause of this :\ gonna seek a solution

from kaop-ts.

Enough arguments by @alexjoverm to close this, thanks mate

from kaop-ts.

Agree. Best contributor ever

from kaop-ts.

Another painless workarround

More info
angular/angular-cli#2034 (comment)

from kaop-ts.

Thanks guys! Appreciate it.

The workaround does the trick.

from kaop-ts.