const arr = ['a','b']

  const num = [
    ["1","2","3","4"],
    ["11","22","33","44"],
  ]

  const result = [
    { a:"1",b:"11" },
    { a:"2",b:"22" },
    {  a:"3",b:"33" }
  ]

  var ret = []
  for (var i = 0; i < num[0].length; ++i) {
    var obj:any = {}
    obj[arr[0]] = num[0][i]
    obj[arr[1]] = num[1][i]
    ret.push(obj)
  }
  console.log(ret)

result