if string contains part of another string javascript code example

Example 1: javascript string contains function

s = "Hello world";
console.log(s.includes("world"));

Example 2: javascript contains substring

var str = "We got a poop cleanup on isle 4.";
if(str.indexOf("poop") !== -1){
	alert("Not again");
}
//use indexOf (it returns position of substring or -1 if not found)