Firestore Full Text Search Angular

fulltext.ts

// set your term
// return this.options to your template
// see here: https://fireblog.io/blog/post/firestore-full-text-search

const n: any = term.split(' ').length;

// split words for separate searching...
let newTerm: string[] = term.split(' ');

// add each word to search term
const searchTerms: any = [];
for (let i = 0; i < n; i++) {
  let t = newTerm.join(' ');
  if (t) {
    searchTerms.push(t);
  }
  newTerm.shift();
}

// set your fields
const fields = ['content', 'title', 'summary', 'tags'];
this.options = this.orQuery(fields, searchTerms);
}

// combine the queries
orQuery(fields: string[], terms: string[]) {
  const queries: any[] = [];
  fields.forEach((f: string) => {
    terms.forEach((t: string) => {
      queries.push(this.fieldQuery(f, t));
    });
  });
  return combineLatest(queries).pipe(
    map((arr: any) => arr.reduce((acc: any, cur: any) => acc.concat(cur))),
    //map((a: any) => a.sort((a, b) => b.relevance - a.relevance))
    map((a: any) => a.sort((a: any, b: any) => (a > b ? -1 : 1)))
  );
}

fieldQuery(field: string, term: string) {

  let id = firebase.firestore.FieldPath.documentId();
  return this.afs.collection<any>(`_search/posts/${field}`, ref => {
    return ref.orderBy(id).startAt(term).endAt(term + '~').limit(5);
  })
    .snapshotChanges()
    .pipe(
      map((actions: any) => {
        return actions.map((a: any) => {
          a['term'] = a.payload.doc.id.split('_').splice(0, 1) + '...';
          a['titleURL'] = a.payload.doc.data().titleURL;
          return a;
        })
      }),
      take(1),
      debounceTime(200)
    );
}

thanks