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Javascript – is there a better shorthand for toggling the existance of an item inside an array?

I often have to check if an item is part of an array. If it is, I would like to remove it. If it’s not, then it should be added. Essentially its toggling the existence of a given item in the array.

const onDateSelected = function (date) {
  const inArray = selectedDates.value.find((d) => d === date) !== undefined;
  if (inArray) {
    selectedDates = selectedDates.filter((d) => d !== date);
  } else {
    selectedDates.push(date);
  }
};

Is there a shorter / quicker way to do this?

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2

Answers


  1. 0

    You can try this :

    const onDateSelected = function(date) {
  const index = selectedDates.indexOf(date);
  index !== -1 ? selectedDates.splice(index, 1) : selectedDates.push(date);
};
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  2. 0

    Using a Set makes this a lot easier using has, delete and add:

    const data =  new Set([ 'foo', 'bar', 'foobar' ]);
const removeOrAdd = 'bar';

if (data.has(removeOrAdd)) {
    data.delete(removeOrAdd)
} else {
    data.add(removeOrAdd)
}

console.log([...data]);

    If you really need an array, consider using indexOf combined with splice

    const data = [ 'foo', 'bar', 'foobar' ];
const removeOrAdd = 'bar';

const possibleIndex = data.indexOf(removeOrAdd);

if (possibleIndex > -1) {
    data.splice(possibleIndex, 1);
} else {
    data.push(removeOrAdd);
}

console.log(data);
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