getIndexesOfAllDuplicates(array): number[]

Returns indexes of every duplicate instance of each item in array.
Any item in array that is object will be considered unique.
Will not work if array contains null or undefined.

Examples

let arr = [1, 2, 3, 4, 1, 2, 3, 4, 1, 2, 3, 4];
getIndexesOfAllDuplicates(arr);
// --> [4, 5, 6, 7, 8, 9, 10, 11]

arr = [ [1, 2], [3, 4], [1, 2], [3, 4], [1, 2], [3, 4] ];
getIndexesOfAllDuplicates(arr);
// --> [2, 3, 4, 5]

arr = [ [1, 2, 'r'], [3, 4], [1, 2], [3, 4], [1, 2, 'r'], [3, 4] ];
getIndexesOfAllDuplicates(arr);
// --> [3, 4, 5]

// Any objects, even if identical, are considered unique:
arr = [ {prop: 1}, {prop: 1} ];
getIndexesOfAllDuplicates(arr);
// --> []

arr = [ [1, 2, {prop: 1}], [3, 4], [1, 2], [3, 4], [1, 2, {prop: 1}] ];
getIndexesOfAllDuplicates(arr);
// --> [3]

// The function won't work with null or undefined:
arr = [null, [3, 4], null, false, [1, 2], [1, 4], false];
getIndexesOfAllDuplicates(arr);
// Error: "Input must be either a primitive type or an array"

Installation

npm install @writetome51/get-indexes-of-all-duplicates

Loading

// if using TypeScript:
import { getIndexesOfAllDuplicates } from '@writetome51/get-indexes-of-all-duplicates';
// if using ES5 JavaScript:
var getIndexesOfAllDuplicates = 
    require('@writetome51/get-indexes-of-all-duplicates').getIndexesOfAllDuplicates;

License

MIT