find a string in an array javascript

var myarr = ["I", "like", "turtles"];
var arraycontainsturtles = (myarr.indexOf("turtles") > -1);

var fruits = ["Banana", "Orange", "Apple", "Mango"];

var a = fruits.indexOf("Apple");
 

function checkInput(input, words) {
 return words.some(word => input.toLowerCase().includes(word.toLowerCase()));
}

console.log(checkInput('"Definitely," he said in a matter-of-fact tone.', 
["matter", "definitely"]));

function checkInput(input, words) {
 return words.some(word => new RegExp(word, "i").test(input));
}

console.log(checkInput('"Definitely," he said in a matter-of-fact tone.', 
["matter", "definitely"]));