JavaScript: Moving elements inside an array, modifying the array in place

If you want to move an element inside an array, neither JavaScript/ES6+ nor libraries like LoDash offet that natively.

Here is a simple function instead that modifies the input array in place.

function moveArrayElement(array, element, offset) {
  const index = array.indexOf(element)
  const newIndex = index + offset
  
  if (newIndex > -1 && newIndex < array.length) {
    // Remove the element from the array
    const removedElement = array.splice(index, 1)[0]

    // At "newIndex", remove 0 elements and insert the removed element
    array.splice(newIndex, 0, removedElement)
  }
}

Pass the element you want to move, and define the move offset (negative to move towards the beginning):

const list = [object1, object2, object3]
moveArrayElement(list, object2, 1)
// list => [object1, object3, object2]
moveArrayElement(list, object2, -2)
// list => [object2, object1, object3]

Note that any calls which move elements beyond the array's boundaries are ignored. It was what I needed, but you could easily adjust that.

Check the linked StackOverflow post for more information and other implementations.