Laravel and VueJS select depending of another select

HTML

<select class="form-control" data-selectField="sales_invoices_customer_id" id="sales_invoices_customer_id" v-model="form.sales_invoices_customer_id" @change="loadSalesMan()"  >
   <option v-for="(cvalue,cindex) in customer_lists" :value="cvalue.id" > {{cvalue.sales_customer_name}}</option>
</select>

<select disabled class="form-control" data-selectField="sales_man_id" id="sales_man_id" v-model="form.sales_man_id" >
  <option v-for="(value,index) in sales_man_lists" :value="value.id" > {{value.sales_man_name}}</option>
</select>

Vue Js:

data:function(){
     return{
        sales_man_lists: {},

     form:{
          sales_invoices_customer_id: '',
          sales_man_id: '',
      },

    };

 methods:{

loadSalesMan(){
     var _this = this;
     var id= this.form.sales_invoices_customer_id;

     axios.get(base_url+"sales-invoice/"+id+"/sales-man-list").then((response) => {

      if(response.data.length > 0){
          console.log(response.data);
           this.sales_man_lists = response.data;
     document.getElementById("sales_man_id ").disabled = false;

           setTimeout(function () {

      var Select2= {init:function() {$(".select2").select2( {placeholder:            "Please select an option"})}};
      jQuery(document).ready(function() {Select2.init()});

     },100);

       }
    });
  },
},

 mounted(){
      var _this = this;

        $('#addComponent').on('change', '.select2', function (e) {
          var selectedType = $(this),
          curerntVal = !!selectedType.val(),
          dataIndex = $(e.currentTarget).attr('data-selectField');
          if(dataIndex == 'sales_invoices_customer_id'){
              _this.form.sales_invoices_customer_id = selectedType.val();
              _this.loadSalesMan();
          }else if(dataIndex == 'sales_man_id'){
              _this.form.sales_man_id = selectedType.val();
             
      });

},

Database:

Route:

 Route::get('sales-invoice/{id}/sales-man-list','Sales\SalesInvoiceController@getSalesManList');


Controller :

public function getSalesManList($customer_id){

   $salesManDetails = CustomerShopsSalesMan::where('customer_shops_id',$customer_id)->get();
   return $salesManDetails;
}