solution.js

function solution(a) {
 let jumps = 0;
 let i = 0;
 let currrentElement = 0
 let nextElement = -1 ;
 let lastElement = -1 ;
 if(a[i] === 0) return -1
 while (a[i]){
lastElement = currrentElement
 currrentElement = i ;
 jumps++;
 i = i + a[i]
 nextElement = i
 if (lastElement === nextElement )
 return -1
 }
 return jumps
}