check for substring javascript

var string = "foo",
    substring = "oo";

console.log(string.includes(substring));const string = "javascript";
const substring = "script";

console.log(string.includes(substring));  //truevar str = "Hello world, welcome to the universe.";
var n = str.includes("world");const string = "foo";
const substring = "oo";

console.log(string.includes(substring));var str = "Hello world, welcome to the universe.";
var n = str.includes("world");
 var str = "We got a poop cleanup on isle 4.";
if(str.indexOf("poop") !== -1){
	alert("Not again");
}