how to check if a substring is in string in js code example

Example 1: check if word is in string javascript

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

Example 2: js check if string contains character

"FooBar".includes("oo"); // true

"FooBar".includes("foo"); // false

"FooBar".includes("oo", 2); // false