1394-find-lucky-integer-in-an-array

DevGod
Elf Vtuber
/** * @param {number[]} arr * @return {number} */var findLucky = function(arr) { return _.toPairs( _.countBy(arr) ).filter( (el)=>Number(el[0])==el[1] ).sort( (el)=>-el[1] )[0]?.[1] ?? -1};