Angular 9 How to delete a range of objects inside an array having indexes range specified by a user?

Question

I am trying to remove objects from an array of objects using a user specified indexes. When a user specify a range between m and n, that's mean that all array having indexes less than m or higher then n, I want them to be deleted from the array.

I tried the following when (m=0 and n=7):

for (const array in this.data) {
  if (parseInt(array) <= 0 || parseInt(array) >7) {
    this.data.splice(parseInt(array))
  }
}
console.log(this.data)

And it's working properly, but once I change m into 1, all the array is emptied.

Here is a stackblitz.

Answer 1

Your main problem is to get the remaining object after deleting. Here Array.slice function comes for the rescue.

Array.slice does not modify the original array. It just returns a new array of elements which is a subset of the original array.

Array.slice signature

arr.slice(startIndex, endIndex);

Consider the following array:

const arr = [0, 1, 2, 3, 4, 5, 6, 7, 8];

To get a slice of an array from values [2, 3, 4, 5], we write:

var slicedArr = arr.slice(2, 6);

Notice that, here, we gave the second argument as 6 and not 5. After executing the above code, we get the values as:

arr // [0, 1, 2, 3, 4, 5, 6, 7, 8]
slicedArr // [2, 3, 4, 5]