Check if value is in select list with JQuery

Use the Attribute Equals Selector

var thevalue = 'foo';
var exists = 0 != $('#select-box option[value='+thevalue+']').length;

If the option's value was set via Javascript, that will not work. In this case we can do the following:

var exists = false;
$('#select-box option').each(function(){
    if (this.value == 'bar') {
        exists = true;
        return false;
    }
});

I know this is kind of an old question by this one works better.

if(!$('.dropdownName[data-dropdown="' + data["item"][i]["name"] + '"] option[value="'+data['item'][i]['id']+'"]')[0]){
  //Doesn't exist, so it isn't a repeat value being added. Go ahead and append.
  $('.dropdownName[data-dropdown="' + data["item"][i]["name"] + '"]').append(option);
}

As you can see in this example, I am searching by unique tags data-dropdown name and the value of the selected option. Of course you don't need these for these to work but I included them so that others could see you can search multi values, etc.

if ($select.find('option[value=' + val + ']').length) {...}

Having html collection of selects you can check if every select has option with specific value and filter those which don't match condition:

//get select collection:
let selects = $('select')
//reduce if select hasn't at least one option with value 1
.filter(function () { return [...this.children].some(el => el.value == 1) });