dailyprogrammer/lib/challenges/JSONChallengeProvider.ts

The /r/dailyprogrammer Tool provides you with a cli to quickly initialize programming challenges and publish them.

import {IChallengeProvider} from "./IChallengeProvider";
import {Difficulty} from "./Difficulty";
import {IChallenge} from "./IChallenge";

export class JSONChallengeProvider implements IChallengeProvider {
    private static _challenges: IChallenge[];
    get challenges(): IChallenge[] {
        if (!JSONChallengeProvider._challenges) {
            JSONChallengeProvider._challenges = this.loadChallenges();
        }
        return JSONChallengeProvider._challenges;
    }

    getAll(difficulty?: Difficulty): Promise<IChallenge[]> {
        return Promise.resolve(this.challenges)
            .then(challenges => {
                if (difficulty) {
                    return challenges.filter(c => c.difficulty === difficulty);
                }

                return challenges;
            });
    }

    get(id: number, difficulty?: Difficulty): Promise<IChallenge[]> {
        return Promise.resolve(this.challenges)
            .then(challenges => challenges.filter(c => {
                if( difficulty != null && c.difficulty !== difficulty ) {
                    return false;
                }

                return c.id === id;
            }));
    }

    private loadChallenges() {
        return require('../../data/challenges.json')
            .map((item) => <IChallenge>{
                date: new Date(item.date),
                description: item.description,
                difficulty: Difficulty[Difficulty[item.difficulty]] || Difficulty.Unknown,
                id: item.id,
                uniqid: `${item.id}_${item.difficulty}`,
                link: item.link,
                title: item.title
            });
    }
}