JSFiddle - React, Tailwind, and code Playground

HTML

<div class="output"></div>
<div class="result"></div>

JavaScript

var groups = [
    {name: 'fruits', words:["apple","strawberry", "banana"]},
    {name: 'test', words:["asd","qwe"]}
];

var searchwords = ["apple", "strawberry"];

// Initialize empty array
var res = Array(groups.length).fill(0);
// Initialize a counter
var biggestIndex;
var biggestValue = 0;

for(i = 0; i < groups.length; i++) {
    for(j = 0; j < groups[i].words.length; j++) {
        if(searchwords.includes(groups[i].words[j]) == true){
            res[i] += 1;
            if(res[i] > biggestValue){
                biggestValue = res[i];
                biggestIndex = i;
            }
        }
    }
}

// biggestIndex holds the index with the most matches
document.querySelector(".output").textContent = "The best group is \"" + groups[biggestIndex].name + "\" group";

// Res holds the list output
document.querySelector(".result").textContent = res;