xotic750 / find-index-x Goto Github PK

This method returns the index of the first element in the array that satisfies the provided testing function.

Like findIndex, this method returns an index in the array, if an element in the array satisfies the provided testing function. Otherwise -1 is returned.

Kind: Exported member
Returns: number - Returns index of positively tested element, otherwise -1.
Throws:

• TypeError If array is null or undefined-
• TypeError If callback is not a function.

Example

import findIndex from 'find-index-x';

function isPrime(element, index, array) {
  let start = 2;
  while (start <= Math.sqrt(element)) {
    if (element % start < 1) {
      return false;
    }

    start += 1;
  }

  return element > 1;
}

console.log(findIndex([4, 6, 8, 12, 14], isPrime)); // -1, not found
console.log(findIndex([4, 6, 7, 12, 13], isPrime)); // 2