Question 50790 in Javascript Question posted in
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How to insert and delete elements from an array by position, while updating positions – Javascript

I have an array of objects with a position property along with other properties like this:

[{position: 1, ...otherProperties}, ...otherObjects]

In the frontend, the objects are displayed and sorted by their position.

I am looking for JavaScript functions to perform the following operations:

  1. Insert a new object at a specified position (e.g., before the element with position: 1) and update the positions of the other elements accordingly (e.g., previous position: 1 element will now be position: 2).
  2. Delete an object from a specified position and update the positions of the remaining elements accordingly.

I am struggling with the creation of these functions

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2

Answers


  1. 0

    You can create two functions addElement and removeElement to add or delete elements in your array, while ensuring the positions are sorted correctly. For example:

    function addElement(arr, newPosition, newElement) {
  // Add a new element at the given position
  newElement.position = newPosition;
  arr.push(newElement);

  // Sort the array by position
  arr.sort((a, b) => a.position - b.position);

  // Update the position of elements
  arr.forEach((item, index) => {
    item.position = index + 1;
  });

  return arr;
}

function removeElement(arr, positionToRemove) {
  // Remove the element from the given position
  arr = arr.filter(item => item.position !== positionToRemove);

  // Update the remaining elements' positions
  arr.forEach((item, index) => {
    item.position = index + 1;
  });

  return arr;
}

    Usage:

    let array = [
  { position: 1, prop: "a" },
  { position: 2, prop: "b" },
  { position: 3, prop: "c" },
];

let newArray = addElement(array, 1, { prop: "d" });
console.log(newArray);

newArray = removeElement(newArray, 3);
console.log(newArray);
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  2. 0

    You need a method that parse all items of your array and set the new position to all of it.

    function fixPosition(arr) {
  arr.map((o, i) => o.pos = i+1)
  return arr
}
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