grouper.js

var arr = []

for(var start = 0; start < 9675; start++) {
	arr.push(start)
}

function convertArrToObject (arr, groupSize=100) {
	
	var count = Math.floor(arr.length / groupSize) + 1
  var obj = {}
  var start = 0
  var end = arr.length -1 < groupSize - 1 ? arr.length -1 : groupSize  - 1
  
  while(count > 0) {
  	obj[`${start}-${end}`] = arr.slice(start, end+1)
    start += groupSize
    end = end + groupSize > arr.length - 1  ? arr.length-1 : end + groupSize
    count -= 1
  }
  
  return obj
}

console.log(convertArrToObject(arr))