TypeScript - remove element from array by index

In TypeScript, it is not intuitive at the first time how to remove element by index. Remove the element by index operation can be achieved with Array.prototype.splice method. This article is focused on how to do it.

Quick solution:

array.splice(index, 1);  // removes 1 element

Where:

• array - from this array we want to remove an element,
• index - removed element index,
• 1 - means the amount of the removed elements - we remove 1 element.

1. Practical example method example

//  index:                0    1    2    3
const array: string[] = ['a', 'b', 'c', 'd'];

// removes 3rd element
const removedElements: string[] = array.splice(2, 1); // removed from index: 2, removed elements amount: 1

console.log(array);
console.log(removedElements);

Output:

['a', 'b', 'd']
['c']

Array.prototype.splice(index, count) method:

• takes:
  • index - starting from this index elements will be removed,
  • count - number of the elemnts to remove starting from index,
• returns:
  • array with removed elements
• warning:
  • splice() method middifies array

2. Reusable function

const removeItem = (array: string[], index: number): string => {
  const items: string[] = array.splice(index, 1);
  if (items.length > 0) {
    return items[0];
  }
  return null;
};

// Usage example:

//           index:       0    1    2    3
const array: string[] = ['a', 'b', 'c', 'd'];

const removedItem: string = removeItem(array, 2);

console.log(array);
console.log(removedItem);

Output:

['a', 'b', 'd']