Toggle element in array

Angelos Chalaris · JavaScript, Array · Apr 15, 2022

Removes an element from an array if it's included in the array, or pushes it to the array if it isn't.

  • Use Array.prototype.includes() to check if the given element is in the array.
  • Use Array.prototype.filter() to remove the element if it's in the array.
  • Use the spread operator (...) to push the element if it's not in the array.
const toggleElement = (arr, val) =>
  arr.includes(val) ? arr.filter(el => el !== val) : [...arr, val];
toggleElement([1, 2, 3], 2); // [1, 3]
toggleElement([1, 2, 3], 4); // [1, 2, 3, 4]

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