Validating form input

Validating the input means checking whether the data entered in the input components satisfies a set of predefined rules. This process has many benefits, such as ensuring the right format of data is being submitted, guiding the users to put the correct values in the correct fields, and saving resources by preventing specific logic from happening if the data is not valid. It also prevents some malicious activity that could arise from certain input.

Let’s take a login page as an example. On the login page, you ask the user to enter an email address and password, then you check whether they are valid. The first thing to check is whether the email address is a valid email address and that it’s not any random text value. The same applies to the password; you have rules such as the minimum number of characters and different types of characters required.

By defining these rules for the form, you ensure that you will receive the data in the correct...