CODEWITHSUNDEEP
javascriptarraystypescriptfilter
notAChance
notAChance

Reputation: 1430

array.filter() and array.some() not acting as expected with an '||' condition

Here is a working example (and here is a link to something you can play with):

  var idDateArray = [
  {
    id: '1',
    updateTime: '00:00:00.000Z',
    updateDate: '2019-01-01'
  },
  {
    id: '2',
    updateTime: '00:00:00.000Z',
    updateDate: '2021-01-01'
  },
  {
    id: '3',
    updateTime: '00:00:00.000Z',
    updateDate: '2019-01-01'
  },
  {
    id: '4',
    updateTime: '00:00:00.000Z',
    updateDate: '2019-01-01'
  },
  {
    id: '5',
    updateTime: '00:00:00.000Z',
    updateDate: '2020-01-01'
  }
]

var itemArray = [
      {
        updateDate: '2020-01-01',
        updateTime: '00:00:00.000Z',
        id: '4'
      },
      {
        updateDate: '2020-01-02',
        updateTime: '00:00:00.000Z',
        id: '2'
      },
      {
        updateDate: '2021-01-02',
        updateTime: '00:00:00.000Z',
        id: '3'
      },
      {
        updateDate: '2020-01-01',
        updateTime: '00:00:00.000Z',
        id: '1'
      }
    ]
 
 var filteredArray = idDateArray.filter((row) =>
        itemArray.some(
            (item) =>
              //item.id !== row.id || // <-LINE IN QUESTION
                (item.id === row.id &&
                    Date.parse(row.updateDate + 'T' + row.updateTime) >
                        Date.parse(item.updateDate + 'T' + item.updateTime)),
        ),
    );

    console.log(filteredArray);

What I am not understanding is why this || condition won't work as I expect? In the above example, when the LINE IN QUESTION is removed, all objects in idDateArray whose id matches those in itemArray AND date/time is > those in itemArray should be removed. And they are (id 2 is all that is left).

I then add in the or condition, which I would then expect to not only filter on matched id's and greater than date time, but also filter those that dont have any match on id. I.E. If either condition is true, remove from idDateArray.

Upvotes: 1

Views: 44

Answers (1)

dave
dave

Reputation: 64695

I mean, you're saying "keep it if there is any item in the array where item.id !== row.id", and there's presumably always going to be at least a single item where the id doesn't match, you're using .some not .every

Upvotes: 2

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