Now it is time to replace recent hardcoded values for the corpus with real functions, so open the evidence service and add the following modifications to it:
// src/app/evidence/evidence.service.ts
//...
@Injectable()
export class EvidenceService {
private corpusSize;
private corpus: FirebaseListObservable <any>;
private IDFs: FirebaseListObservable <any>;
//...
constructor(http: Http, af: AngularFire) {
this.http = http;
this.angularFire = af;
this.corpus = af.database.list('Evidence/Corpus/Articles');
this.IDFs = af.database.list('Evidence/Corpus/IDFs');
}
corpusBuilder(keywords) {
// ToDo:
// 1. Fetch links for each keyword
// 2. Pass the link to EvidenceService for extracting contents
// 3. Save them under corpus key for further caluculation
}
}
Please notice that we have created two children under the Evidence/Corpus key. Apart from articles, we need to keep all IDF calculations somewhere...