Instructor: We have this simple React application with a name input. The value of that input is stored in the nameState variable, and it's passed down to the input component. The handleNameChange updates the nameState variable.
We want to prevent the user from typing any character that is not a letter or a space character into the input. We want to filter out all of the numbers and special characters. We don't want to have this as a possible value of the name.
To achieve that we'll go to the handleNameChange function, and create a new variable here called newName. Its value will be event, target, value. We use this new variable in the setName call, setName(newName).
To filter out the unwanted characters, we'll call replaceOnValue. We'll give it a regular expression pattern, and we'll replace every character that matches that pattern with an empty string, essentially removing that character.
We can now see that we can input a normal name value, but if we try to input something like a number or a special character, it's not being added at all, no matter where we try to add it.