TypeScript lodash.sampleSize函數代碼示例

export function* recommendSaga () {
  const isLogin = yield call(api.getUserId)
  const promises = [
    api.topPlayList('30'),
    api.newAlbums('30'),
    api.topArtists('30')
  ]
  if (isLogin) {
    promises.push(api.dailyRecommend('30'))
  }

  yield put({
    type: 'home/recommend/start'
  })

  try {
    const [
      playlists,
      albums,
      artists,
      songs
    ] =  yield call(Promise.all, promises)

    if (playlists.code === 200) {
      yield put({
        type: 'playlists/sync/save',
        payload: changeCoverImgUrl(playlists.playlists),
        meta: {
          more: true,
          offset: 0
        }
      })
    }

    if (albums.code === 200 && artists.code === 200) {
      yield put({
        type: 'home/recommend/save',
        payload: {
          albums: sampleSize(albums.albums, 6),
          artists: sampleSize(artists.artists, 6)
        }
      })
    }

    if (songs && songs.code === 200) {
      yield put({
        type: 'personal/daily/save',
        payload: songs.recommend.slice(0, 6)
      })
    }
  } catch (error) {
    yield put(toastAction('error', '網絡出現錯誤..'))
  }

  yield put({
    type: 'home/recommend/end'
  })
}

    return _.reduce(categories, function(total, category) {
        const categoryQuestionsIds = _.map(category.questions, 'id');
        const unplayedQuestionsIdsInCategory = _.difference(categoryQuestionsIds, playedQuestionsIds);
        let replayedQuestionsIdsInCategory = [];
        if (unplayedQuestionsIdsInCategory.length < category.questionsCount) {
            //we don't have enough unplayed questions, we have to reuse played ones
            const replayedQuestionsCount = category.questionsCount - unplayedQuestionsIdsInCategory.length;
            replayedQuestionsIdsInCategory = _.sampleSize(_.intersection(categoryQuestionsIds, playedQuestionsIds), replayedQuestionsCount);
        }
        const selectedCategoryQuestionsIds = _.sampleSize(replayedQuestionsIdsInCategory.concat(unplayedQuestionsIdsInCategory), category.questionsCount);

        const selectedQuestionsInCategory = _.filter(category.questions, question => _.includes(selectedCategoryQuestionsIds, question.id));
        total = total.concat(selectedQuestionsInCategory);
        return total;
    }, [])

 it('should return undefined if station is invalid', () => {
   _.sampleSize(Object.keys(stationInfo), 10)
     .map(station => station + 'random-crap')
     .forEach(invalidStation =>
       expect(StationManager.getStation(invalidStation)).toBe(undefined)
     )
 })

 async getKillerLoadout(): Promise<ILoadout> {
   return {
     item: await this.getRandomKiller(),
     offering: null,
     perks: _.sampleSize( (await this.fetch()).killers.perks, 4 )
   };
 }

 async getRandomKiller(): Promise<TKiller> {
   const killers = (await this.fetch()).killers;
   const killer = _.sample( killers.abilities );
   return _.extend({}, killer, {
     addons: _.sampleSize( killers.addons[ killer.name.replace(/The\s/, '') ], 2 )
   });
 }

 async getSurvivorLoadout(): Promise<ILoadout> {
   return {
     item: await this.getRandomItem(),
     offering: null,
     perks: _.sampleSize( (await this.fetch()).survivors.perks, 4 )
   };
 }

 async getRandomItem(): Promise<TItem> {
   const survivors = (await this.fetch()).survivors;
   const item = _.chain(survivors.items).sample().sample().value();
   return _.extend({}, item, {
     addons: _.sampleSize( survivors.addons[ item.type ], 2 )
   });
 }

      it('should call TripManager for trip options, passing "to" and "from" stations, and date', async () => {
        const [fromStationName, toStationName] = _.sampleSize(Object.keys(stationInfo), 2)
        await API.Trips.getTripOptions(fromStationName, toStationName, moment().toDate())

        expect(TripManager.getTripOptionsFromNJTPage).toHaveBeenCalled()
        const [fromStation, toStation, date] =
          (TripManager.getTripOptionsFromNJTPage as jest.Mock<Promise<Trip[]>>).mock.calls[0]
        expect(fromStation).toEqual(stationInfo[fromStationName])
        expect(toStation).toEqual(stationInfo[toStationName])
        expect(moment().diff(moment(date))).toBeLessThan(1000) // Verify dates are less than 1s apart (close enough)
      })

export function getFakeAnswers(count: number) {
    return _.sampleSize(fakeAnswersArray, count);
}