Form validation is natively supported by the browser, but sometimes different browsers will handle things in a manner which makes relying on it a bit tricky. Let’s look at the HTML first: is a temporary URL that would point to something real on a server someplace (where you have backup server-side validation of course).Even when validation is supported perfectly, there may be times when custom validations are needed and a more manual, Vue-based solution may be more appropriate. Beneath that there is a paragraph that shows or hides itself based on an error state.Validation of data is an interesting topic, we tend to write code that looks really horrible in the sense that it contains a lot of checks. Well, Joi supports all sorts of primitives as well as Regex and can be nested to any depth.There are different situations when we need to perform these checks like validating a response from a backend endpoint or maybe verifying what goes into our REST API won’t break our code. Let’s list some different constructs it supports: property, that thing looks exactly like the outer call we first make and it is the same. Libraries like these are great but wouldn’t it be even better if we could use them in a more seamless way, like in a Request pipeline?Ok, great we can deal with BODY in POST request what about router parameters and query parameters and what would we like to validate with them: , our other requirement: Also, that fails, as expected.We have introduced the validation library Joi and presented some basic features and how to use it.
Once we’ve got those utilities we can define the main validation function, which tests the field and then performs the actual validation, if applicable: attribute to indicate that state – adding it to an invalid field that doesn’t already have it, or removing it from a valid field that does. Finally, to put this all into action, we need to bind the validation function to an .
The final thing to note is that each of the three fields has a corresponding logic (which is run on submit remember) checks for name and age only as movie is optional. Don’t forget that on a successful submission it’s going to POST to a temporary URL.
If they are empty we check each and set a specific error for each. See the Pen form validation 1 by Raymond Camden (@cfjedimaster) on Code Pen.
For example, I’ve seen forms where it’s impossible to ) to force the focus to stay inside the field until it’s valid.
This is very poor usability, and directly contravenes accessibility guidelines.