getReverseIndex(
      index,
      arrayLength
): number

Receives array index and returns the new index that same item would have
if the array's order were reversed.

Examples

let arr = ['a', 'b', 'c', 'd', 'e'];   
let index = arr.indexOf('d');
getReverseIndex(index, arr.length);
   // -->  1

arr = [7, 2, 6, 9, 3, 10];
index = arr.indexOf(2);
getReverseIndex(index, arr.length);
   // -->  4

Installation

npm i @writetome51/get-reverse-index

Loading

import {getReverseIndex} from '@writetome51/get-reverse-index';