JSFiddle - React, Tailwind, and code Playground

HTML

<div class="a">Hello</div>
<div class="a">Stack</div>
<div class="a">Overflow</div>

<div class="b">Have</div>
<div class="b">a</div>
<div class="b">nice</div>
<div class="b">day!</div>

<div class="c">Bye bye</div>

JavaScript

$(function() {
    function inArray(item, arr) {
        for (var i = 0; i < arr.length; i++) {
            var items = $.makeArray(arr[i]);
            
            for (var k = 0; k < items.length; k++) {
                if (items[k] == item[0]) {
                    return true;
                }
            }
        }
        
        return false;
    }
    
    console.log(inArray($(".a").eq(2), [$(".a"), $(".b")])); // true
    console.log(inArray($(".b").eq(3), [$(".a"), $(".b")])); // true
    console.log(inArray($(".c"), [$(".a"), $(".b")]));       // false
    console.log(inArray($(".a").eq(2), [$(".b")]));          // false
    console.log(inArray($(".a").eq(2), []));                 // false
    console.log(inArray($(".c"), [$("div")]));               // true
});