You have one easy way.
Every string has an
includes() method that accepts one (or more) characters.
This method returns
true if the string contains the character, and
false if not:
'a nice string'.includes('a') //true 'a nice string'.includes('b') //false
If you need to find the exact position of the letter in the string, however, you need to use the
'a nice string'.indexOf('a') //0 'a nice string'.indexOf('c') //4
If there are more than one occurrence, this method returns the position of the first one it finds, starting from the left.