check for substring javascript

1const string = "javascript";
2const substring = "script";
3
4console.log(string.includes(substring));  //true

1var string = "foo",
2    substring = "oo";
3
4console.log(string.includes(substring));

1var str = "We got a poop cleanup on isle 4.";
2if(str.indexOf("poop") !== -1){
3	alert("Not again");
4}
5//use indexOf (it returns position of substring or -1 if not found)

1
2var str = "Hello world, welcome to the universe.";
3var n = str.includes("world");
4 

1var str = "We got a poop cleanup on isle 4.";
2if(str.indexOf("poop") !== -1){
3	alert("Not again");
4}

1var string = "foo",
2var substring = "oo";
3
4console.log(string.includes(substring));