codility lesson 4 perm check

function solution(A) {
    A.sort(function(a,b){return a-b})
    count=0
    for(i=0; i<A.length; i++){
        if(A[i]===i+1){
            count++
        }else{
            break
        }
    }
    
    if(count===A.length){
            return 1
        }else{
            return 0
        }
}