用filter和一些對象過濾另一個對象數組

Question

我有一個這樣的對象數組

events = [ {
    'summary': 'sample test events1',
    'location': 'coimbatore',
    'start': {
        'date': '2018-08-28',
        'timeZone': 'America/Los_Angeles'
    },
    'end': {
        'date': '2018-08-28',
        'timeZone': 'America/Los_Angeles'
    }
    },
    {
      'summary': 'sample test events2',
      'location': 'coimbatore',
      'start': {
          'date': '2018-08-29',
          'timeZone': 'America/Los_Angeles'
      },
      'end': {
          'date': '2018-08-29',
          'timeZone': 'America/Los_Angeles'
      }
    },
    {
    'summary': 'sample test events4',
    'location': 'coimbatore',
    'start': {
        'date': '2018-08-27',
        'timeZone': 'America/Los_Angeles'
    },
    'end': {
        'date': '2018-08-27',
        'timeZone': 'America/Los_Angeles'
    }
    },
    {
      'summary': 'sample test events5',
      'location': 'coimbatore',
      'start': {
          'date': '2018-08-26',
          'timeZone': 'America/Los_Angeles'
      },
      'end': {
          'date': '2018-08-26',
          'timeZone': 'America/Los_Angeles'
      }
      }];

我還有另一個要過濾的對象數組

toFilterEvents = [
{startDate: "2018-08-28", summary: "sample test events1"},
{startDate: "2018-08-29", summary: "sample test events2"},
]

我希望結果像

events = [ 

    {
    'summary': 'sample test events4',
    'location': 'coimbatore',
    'start': {
        'date': '2018-08-27',
        'timeZone': 'America/Los_Angeles'
    },
    'end': {
        'date': '2018-08-27',
        'timeZone': 'America/Los_Angeles'
    }
    },
    {
      'summary': 'sample test events5',
      'location': 'coimbatore',
      'start': {
          'date': '2018-08-26',
          'timeZone': 'America/Los_Angeles'
      },
      'end': {
          'date': '2018-08-26',
          'timeZone': 'America/Los_Angeles'
      }
      }];

我嘗試過的

filterExistingEvents(toFilterEvents);

filterExistingEvents(filtered_events) {
    const hello = this.events.filter((r, i) => {
      return filtered_events.some(f => r.summary !== f.summary)
    });
    console.log('events after filter', hello, this.events);  
}

如您所見，我正在使用過濾器和一些過濾器來獲得所需的輸出，如上所示，但它不起作用。 我發現了類似的問題，但這是返回沒有toFilterEvents的事件

Answer 1

Array.prototype.some返回true ，如果數組元素的ATLEAST一個相匹配的條件Array.prototype.every返回true ，如果所有的數組元素的條件匹配

filterExistingEvents(filtered_events) {
    const hello = this.events.filter((r, i) => {
      return filtered_events.every(f => r.summary !== f.summary)
    });
    console.log('events after filter', hello, this.events);  
}

Answer 2

看起來您想對多個字段進行過濾，因此最好從高階函數中創建過濾器函數，有關詳細示例，請參見此處 。

我認為您實際上是在尋找某些而非全部的反轉。

 const events = [{ 'summary': 'sample test events1', 'location': 'coimbatore', 'start': { 'date': '2018-08-28', 'timeZone': 'America/Los_Angeles' }, 'end': { 'date': '2018-08-28', 'timeZone': 'America/Los_Angeles' } }, { 'summary': 'sample test events2', 'location': 'coimbatore', 'start': { 'date': '2018-08-29', 'timeZone': 'America/Los_Angeles' }, 'end': { 'date': '2018-08-29', 'timeZone': 'America/Los_Angeles' } }, { 'summary': 'sample test events4', 'location': 'coimbatore', 'start': { 'date': '2018-08-27', 'timeZone': 'America/Los_Angeles' }, 'end': { 'date': '2018-08-27', 'timeZone': 'America/Los_Angeles' } }, { 'summary': 'sample test events5', 'location': 'coimbatore', 'start': { 'date': '2018-08-26', 'timeZone': 'America/Los_Angeles' }, 'end': { 'date': '2018-08-26', 'timeZone': 'America/Los_Angeles' } }]; const filterFn = getter => comparer => o => comparer(getter(o)) ; const isNotIn = hayStack => needle => !hayStack.some(x=>x===needle) ; const summary = o => o.summary; const startDate = o => o.start.date; const toFilterEvents = [ { startDate: "2018-08-28", summary: "sample test events1" }, { startDate: "2018-08-29", summary: "sample test events2" }, ]; //filter out any events that have summary or startDate in toFilterEvents console.log( events.filter( filterFn(summary)(isNotIn(toFilterEvents.map(x=>x.summary))) ).filter( filterFn(startDate)(isNotIn(toFilterEvents.map(x=>x.startDate))) ).map(x=>x.summary) ); //filter out any events that have summary and startDate in toFilterEvents console.log( events.filter( ( (summaries,startDates)=>item=> filterFn(summary)(isNotIn(summaries))(item) || filterFn(startDate)(isNotIn(startDates))(item) )(toFilterEvents.map(x=>x.summary),toFilterEvents.map(x=>x.startDate)) ).map(x=>x.summary) );