SOURCE

let create = (n)=>{
  return Array(n).fill('').map((el,i)=>{
    return {
      code: ''+i,
      items: Array(Math.floor(Math.random()*10)+1).fill('').map((el,i)=>{
        return {
          u: Math.floor(Math.random()*100)
        }
      })
    }
  })
}
let arr = create(1000000)
console.time('best');
// console.profile('1')
/* arr.sort((a, b) => {
    const aMin = a.items.sort((a, b) => a.u - b.u)[0].u
    const bMin = b.items.sort((a, b) => a.u - b.u)[0].u
    return aMin - bMin
}) */

let tar = []
arr.forEach(e=>{
    let i = e.items.reduce((last,item)=>(item.u+last),0)
    tar[i] = e
})
arr = Object.values(tar)
console.timeEnd('best')
// console.profileEnd('1')
// console.log(arr)