Multiple fields validations on rails5

[no1-knows]

I'm a newbie using rails.
First of all thank you for your client_side_validations!
This is very useful.

The multiple-fields wiki page is good for rails5?

https://github.com/DavyJonesLocker/client_side_validations/wiki/Shared-validations-for-multiple-fields

I tried and get error message like 'undefined method `-' for nil:NilClass' at below code.

def great_small_fields_diff
        great_field - small_field
 end

I can't judge this is because of rails version or not but I'm worried about published date which is 2012...

[tagliala]

Hi,

'undefined method -' for nil:NilClass'means that you are trying to subtractnilto something else. I think your model does not definegreat_field` or its corresponding field. Please take a look to Rails Activee Record Basics

About the wiki: https://github.com/DavyJonesLocker/client_side_validations/wiki/Shared-validations-for-multiple-fields

Quoting from the wiki:

For example you want the value of a field to be greater than another

Well, the example is outdated and I'm not a fan of the approach suggested by that wiki.

If you just need that kind of validation, the numericality validator offers that kind of validation out of the box: https://guides.rubyonrails.org/active_record_validations.html#numericality

validates :small_field, numericality: { greater_than: 0 }
validates :great_field, numericality: { greater_than: :small_field }

It works on the client side in a lot of cases (other cases will be anyhow covered on the server side). Ref: #687

If you really need (check what Rails offers first) special validations, I advise you to create a custom local validator (both server side and client side) as described in this wiki: https://github.com/DavyJonesLocker/client_side_validations/wiki/Custom-Validators and assign it to a specific field.

If the custom validation you need is too complex and the above per-field custom validations are still not enough, consider using a standard jQuery callback when all validations pass and rails is ready to submit the form:

$(document).on('submit', '#my_form', function(e) {
  if (!myValidationFunction()) {
    e.preventDefault();

    myShowErrorFunction();

    // Enable buttons disabled with `disable_with` option
    setTimeout(function() {
      $.rails.enableElement(e.target);
    }, 26)

    return false;
  }

  myHideErrorFunction();
})

Hope it helps

Closing here, but feel free to comment

[no1-knows]

@tagliala thank you for reply!

'undefined method `-' for nil:NilClass’ is solved!
But wiki way doesn’t work because error don’t show up at diplay:none object.

For me, this wiki is easy to understand and your offer, create a custom validator, is difficult for me.

As far as I know, phone, zip code, name or something like that use several fields in form and only 1 table column is used in most cases.
So I hope not to divide these table column.

Is there any easy approach to solve this problem at this awesome gem?

[tagliala]

But wiki way doesn’t work because error don’t show up at diplay:none object.

You should avoid that display:none form field 😅

What you need to validate?

[no1-knows]

Hello!

First of all I am very sorry because I was very confused.
I thought attr_accessor validation doesn't work.
But that was completely wrong after checking new environment.

What I need to validate is zip code, name, phone number .... but my problem is solved.
Thank you for your support!

[tagliala]

You're welcome, glad you've solved