find-last-index-x

Search an array from the end and return the matched index.

Usage no npm install needed!

<script type="module">
  import findLastIndexX from 'https://cdn.skypack.dev/find-last-index-x';
</script>

README

Travis status Dependency status devDependency status npm version jsDelivr hits bettercodehub score Coverage Status

find-last-index-x

Search an array from the end and return the matched index.

module.exports(array, callback, [thisArg]) ⇒ number ⏏

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

Kind: Exported function
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.
Param Type Description
array Array The array to search.
callback function Function to execute on each value in the array, taking three arguments: element, index and array.
[thisArg] * Object to use as this when executing callback.

Example

import findLastIndex from 'find-index-x';

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

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