Javascript: Creating dictionary array using variables for keys and values

I am trying to create a dictionary from some lists using the .push() method.

The result I am trying to achieve is:

{
  "departTo": {
    1: 1.159,
    2: 4.156,
    3: 9.185,
    3: 10.158,
    4: 2.158
  },
  "departTo": {
    1: 2.586,
    2: 5.518,
    3: 11.584,
    3: 7.819,
    4: 3.991
  }
}

Below is a sample of code of what I am trying to do:

console.group("Running Script 1...");

var select_array = [];
var arrive_from, info

var selection_type = ["departTo", "arriveFrom"];
var data_lists_depart = [[1, 1.159], [2, 4.156], [3, 9.185], [4, 10.158], [5, 2.158]];
var data_lists_arrive = [[1, 2.586], [2, 5.518], [3, 11.584], [4, 7.819], [5, 3.991]];

selection_type.forEach(function (selection, i) {
    console.log("selection", i + ": ", selection);
    if (selection === "departTo") data_lists = data_lists_depart;
    else if (selection === "arriveFrom") data_lists = data_lists_arrive;
    data_lists.forEach(function (data_list, ii) {
        console.log("   data_list", ii + ": ", data_list);
        key = data_list[0];
        val = data_list[1];
        select_array.push({selection: {key: val}});
    })
})
console.log("select_array: ", select_array);

console.groupEnd("Running Script 1...");

The result I am getting from the above code is:

[
  {"selection": {"key": 1.159}}, 
  {"selection": {"key": 4.156}}, 
  {"selection": {"key": 9.185}}, 
  {"selection": {"key": 10.158}}, 
  {"selection": {"key": 2.158}}, 
  {"selection": {"key": 2.586}}, 
  {"selection": {"key": 5.518}}, 
  {"selection": {"key": 11.584}}, 
  {"selection": {"key": 7.819}}, 
  {"selection": {"key": 3.991}}
]

Any assistance in getting this into the format I need will be greatly appreciated.
Thank you.