ng2-translate file loader with localstorage to speed up things

translateLSLoader.ts

import {TranslateLoader} from "ng2-translate/ng2-translate";
import {Observable} from "rxjs/Observable";
import {Response, Http} from "angular2/http";

export class TranslateLSLoader implements TranslateLoader {
    constructor(private http: Http, private prefix: string = 'i18n', private suffix: string = '.json') {}

    /**
     * Gets the translations from the localStorage and update them with the ones from the server
     * @param lang
     * @returns {any}
     */
    public getTranslation(lang: string): Observable<any> {
        return Observable.create(observer => {
            let translations = localStorage.getItem('ng2-translate-' + lang);
            if(translations) {
                observer.next(JSON.parse(translations));
            }

            this.http.get(`${this.prefix}/${lang}${this.suffix}`)
                .map((res: Response) => res.json())
                .subscribe((res: any) => {
                    observer.next(res);
                    localStorage.setItem('hmx-lang-' + lang, JSON.stringify(res));
                    observer.complete();
                });
        });
    }
}