How to immutably insert into a sorted array?

Question

How do I immutably insert an element into a sorted array? (Let's assume an array of integers for simplicity)

The reason for this question: I'm writing a reducer for a React app, where the order of elements in my particular array is important.

The closest solution I've found is this one here, but it doesn't cover insertions into a sorted array.

What do you mean by "immutably insert"? Inserting is a mutation. Sounds like you just need to make a copy of the array, insert into the copy, and return that. — Barmar, Sep 11 '19 at 23:13

score 1 · Accepted Answer · answered Sep 11 '19 at 23:17

Try this one.

let sortedArr = [1,2,5,9,12];

const newItem = 7;

for (let i = 0; i < sortedArr.length; i++) {
  if (newItem <= sortedArr[i]) {
    sortedArr = [...sortedArr.slice(0, i), newItem, ...sortedArr.slice(i)];
    break;
  }
}
console.log(sortedArr);

How to immutably insert into a sorted array?

1 Answers1