Magento – Magento2 how to remove “choose an option” in configurable products drop down

Here You Can Make Attribute Selected...If DorpDown Have Only One Attribute.... Bellow of This code

var spConfig = new Product.Config(<?php echo $_jsonConfig ?>);

Put this code....here..

 //we create new function
    spConfig.setInitialState = function (dropdown_id)
    {
        //select dropdown
        var dropdown = $(dropdown_id);
        //remove empty option from dropdown so it is not selectable after initial selection
        // dropdown[0].remove();
        //alert(dropdown.length);
        if (dropdown.length == 2) {
            dropdown[0].remove();// for the removing choose an option
           }
        //change selections in dropdowns
        for (index = 0; index < dropdown.length; index++)
        {
            if (dropdown[index].value != "")
            {
                dropdown.selectedIndex = index;
                var element = dropdown;
                var event = 'change';
                //fire events
                if (document.createEventObject)
                {
                    var evt = document.createEventObject();
                    return element.fireEvent('on' + event, evt)
                } else
                {
                    var evt = document.createEvent("HTMLEvents");
                    evt.initEvent(event, true, true);
                    return !element.dispatchEvent(evt);
                }
            }
        }
    };
<?php foreach ($_attributes as $_attribute): ?>
        spConfig.setInitialState("attribute<?php echo $_attribute->getAttributeId() ?>")
<?php endforeach; ?>

You've to add some code to change the price while changing the drop-down, that file path is www\app\design\frontend\XXX\XXX\Magento_Swatches\web\js, after adding, please do setup upgrade and content-deploy

• Step-1: Add Following code in _EventListener: function () {

  $widget.element.on('change', '.' + this.options.classes.selectClass, function () {
      return $widget._OnChangeCustom($(this), $widget);
  });
  

• Step-2: Add this function

  _OnChangeCustom: function ($this, $widget) {
      var check = $this.val();
      var checkId = '#'+$this.parent().attr('id');
      $(checkId+' option').each(function(){
          var currentValue = $(this).val();
          if(currentValue == check){
              $(this).attr('selected', true);
              $(this).addClass('selected');
              var currentId = $(this).attr('option-id');
              $(checkId+' select').attr('option-selected',currentId);
          }else{
              $(this).removeClass('selected');
              $(this).attr('selected', false);
          }
      });
      $widget._Rebuild();
  
      if ($widget.element.parents($widget.options.selectorProduct)
              .find(this.options.selectorProductPrice).is(':data(mage-priceBox)')
      ) {
          $widget._UpdatePrice();
      }
  
      $widget._LoadProductMedia();
  
  },
  

• Step-3: Add this function

   _LoadProductMedia: function () {
      var $widget = this,
          $this = $widget.element,
          attributes = {},
          productId = 0;
  
      if (!$widget.options.mediaCallback) {
          return;
      }
  
      $this.find('[option-selected]').each(function () {
          var $selected = $(this);
          attributes[$selected.attr('attribute-code')] = $selected.attr('option-selected');
      });
  
      if ($('body.catalog-product-view').size() > 0) {
          //Product Page
          productId = document.getElementsByName('product')[0].value;
      } else {
          //Category View
          //create productId hidden field from list.phtml
          productId = $this.parents('.product.details.product-item-details').find('#productId').val();
      }
  
      var additional = $.parseParams(window.location.search.substring(1));
  
      $widget._XhrKiller();
      $widget._EnableProductMediaLoader($this);
      $widget.xhr = $.post(
          $widget.options.mediaCallback,
          {product_id: productId, attributes: attributes, isAjax: true, additional: additional},
          function (data) {
              var newPrice = data.special;
              var oldPrice = data.price;
              // ** add your price html here to update **
              $widget._ProductMediaCallback($this, data);
              $widget._DisableProductMediaLoader($this);
          },
          'json'
      ).done(function () {
          $widget._XhrKiller();
      });
  },