Searching Strings, Part 2

If I only want to know whether a string contains a substring, includes is enough. But what if I want to know where within the string the substring is found?

JavaScript strings have an indexOf method. It works like includes, but instead of returning true when it finds the substring, it returns the index of the first character in the substring.

Try it. Add this code to the editor and run it:

let str = "Colonize Mars!";
let includes_n = str.includes("n");
let index_n = str.indexOf("n");
console.log("Includes n: ", includes_n);
console.log("Index of n: ", index_n);
console.log("Letter at index of n: ", str[index_n]);

You can look for any substring, not just single characters. But you'll get back the index of the first character in the substring. Add this code to see what I mean:

let index_Mars = str.indexOf("Mars");
console.log("Index of 'Mars': ", index_Mars);
console.log("Letter at index of 'Mars': ", str[index_Mars]);

Now that you understand how indexOf works, try passing the tests described in the starter code comments.