Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

JavaScript

Posted by Kip Yin
Kip Yin
4,847 Points

Check if a letter is in a string

I can check if an array contains a specific element using the keyword in:

> 1 in [1, 2]
true

But this throws an error:

> '1' in '1234456'
TypeError: Cannot use 'in' operator to search for '1' in 1234456

How can I check if something is in a string or not?

Kristian Woods
Kristian Woods
23,414 Points 
// create an array
var arr1 = [1, 2, 3];

// call includes() on the array passing a searchElement
var result = arr1.includes(2);

// log the result
console.log(result);
// expected output: true

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/includes

Kristian Woods
Kristian Woods
23,414 Points

for strings

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/includes

Kip Yin
Kip Yin
4,847 Points

Thanks Kristian! This helped out a lot.