Tips for inserting a value into a specific location within an array using JavaScript

Question

Tips for inserting a value into a specific location within an array using JavaScript

I am working with an array of objects that looks like this:

const array = [
  { id: 1 },
  { id: 2 },
  { id: 3 },
  { id: 4 }
];

My task is to add a new entry to this array, but it needs to be inserted at a specific position. For instance, when adding { id: 5, after_id: 2 }, the new object should be placed between ids 2 and 3. Is there a recommended method for achieving this?

javascript arrays ecmascript-6

Answer 1

Answer №1

@p.s.w.g has shared a great solution in the comments, but I wanted to present my original approach as an answer now that the question is reopened.

To tackle this problem, you can leverage the some method to loop through the array until the desired index is found. Once located, you can slice the array and insert the new item at the specified index:

const arrayTest = [{
    id: 1
  },
  {
    id: 2
  },
  {
    id: 3
  },
  {
    id: 4
  }
];

const insertAfterId = (array, item, idAfter) => {
  let index = 0;
  array.some((item, i) => {
    index = i + 1;
    return item.id === idAfter
  })

  return [
    ...array.slice(0, index),
    item,
    ...array.slice(index, array.length),
  ];
};

const result = insertAfterId(arrayTest, {
   id: 6
}, 2)
console.dir(result)

Answer 2

@p.s.w.g has shared a great solution in the comments, but I wanted to present my original approach as an answer now that the question is reopened.

To tackle this problem, you can leverage the some method to loop through the array until the desired index is found. Once located, you can slice the array and insert the new item at the specified index:

const arrayTest = [{
    id: 1
  },
  {
    id: 2
  },
  {
    id: 3
  },
  {
    id: 4
  }
];

const insertAfterId = (array, item, idAfter) => {
  let index = 0;
  array.some((item, i) => {
    index = i + 1;
    return item.id === idAfter
  })

  return [
    ...array.slice(0, index),
    item,
    ...array.slice(index, array.length),
  ];
};

const result = insertAfterId(arrayTest, {
   id: 6
}, 2)
console.dir(result)

Tips for inserting a value into a specific location within an array using JavaScript

Answer №1

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