rambda/src/findLastIndex.js

Lightweight faster alternative to Ramda

export function findLastIndex(fn, list){
  if (arguments.length === 1) return _list => findLastIndex(fn, _list)

  let index = list.length

  while (--index >= 0){
    if (fn(list[ index ], index)){
      return index
    }
  }

  return -1
}