js array filter based on two boolean conditions

Question

I have two boolean conditions to filter an array. An array will always have 3 items within, and first condition always removes 2nd item, second condition 3rd one. And I successfully filtering it using .filter. But seems my approach a bit dirty, is there any better, clear way to filter?

  const firstCondition = true;
  const secondCondition = true;

  const arrayToFilter: Array<string> = ['firstItem', 'secondItem', 'thirdItem'].filter(
    (item, idx) =>
      firstCondition && secondCondition 
        ? item
        : !firstCondition && secondCondition 
        ? idx !== 1
        : !firstCondition && !secondCondition 
        ? idx === 0
        : firstCondition && !secondCondition && idx !== 2
  );

console.log(arrayToFilter);

Edit: Clarification If Conditions are false they removes items

ValleyCrisps · Accepted Answer · 2022-04-06 06:46:46Z

1

How about this?

 const arrayToFilter: Array<string> = ['firstItem', 'secondItem', 'thirdItem'].filter(
(item, idx) => {
    if (!firstCondition && idx === 1) return false
    if (!secondCondition && idx === 2) return false
    else return true 
  }
);

edited Apr 6, 2022 at 6:46

answered Apr 6, 2022 at 6:00

ValleyCrisps

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2 Comments

Fatdrfrog Over a year ago

Nice, but I've changed logic a bit to fulfill my expectations, to !firstCondition, !secondCondition. Definitely better than what I wrote.

ValleyCrisps Over a year ago

Oh, I see what you mean now. I have updated my answer to fit your edited description.

eamanola · Accepted Answer · 2022-04-06 06:22:43Z

0

try,

....
(item, index) => (
  (firstCondition && index !== 1)
  || (secondCondition && index !== 2)
  || true // (!firstCondition && !secondCondition)
)

edited Apr 6, 2022 at 6:22

answered Apr 6, 2022 at 6:04

eamanola

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3 Comments

Fatdrfrog Over a year ago

Your approach is looking pretty, but seems your first two conditions within brackets() has to return false to properly filtering but they returning true, or I am missing something? I've tried to use it but it gives me wrong result. Like if 1-true, 2-true I see an empty array.

eamanola Over a year ago

yeah, index values were wrong 2 & 3, instead of 1 & 2

Fatdrfrog Over a year ago

No, I've changed them to 1&2 before checking)

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