How to handle validation of multiple hidden fields - php

Question

I have created a form where in many cases some fields are not displayed until user select a certain option that will make the particular field displayed, this is controlled by HTML onchange Event Attribute with functions in script. To this point everything works fine.
Problem:
In the Request class I am implementing some rules for validation , for all displayed fields and for particular none displayed fields if only their options are selected then they should be validated. In my case I have 8 of this none displayed fields are a_text, b_text, c_text, d_text, e_text, f_text,g_text, h_text. If this fields were 2 it would be easy to write an If statement to choose which should be validated and which should not be validated like below:
<?php
namespace App\Http\Requests;
use Illuminate\Foundation\Http\FormRequest;
use Illuminate\Http\Request;
class StoreSectionERequest extends FormRequest
public function rules(Request $request)
{
$a = $request->a;
$b = $request->b;
if($a==5 && $b==3){
return [
//for none displayed fields only validate the below
'a_text' =>'required',
'b_text' =>'required',
//..and other displayed fields will be valuated.
];
}elseif(!$a==5 && $b==3){
return [
//for none displayed fields only validate the below
'b_text' =>'required',
//..and other displayed fields will be valuated.
];
}elseif($a==5 && !$b==3){
return [
//for none displayed fields only validate the below
'a_text' =>'required',
//..and other displayed fields will be valuated.
];
}
// in case all none displayed field are not selected only check other fields below
return [
// validaying all none displyed field here]; }}
In my case I have 8 fields which are none displayed, of which I have to handle all cases of fields if it's selected and not, this will lead to 100's or a lot of if...elseif..statements. What is the wright approach to handle this kind of task.
Form
<form method="POST" action="{{ route('......') }}">#csrf
<div class="row">
<div class="col-md-5" id="lackingSkills">
<label for="">Which skills and competencies graduates are lacking? </label>
<select name="a" multiple="multiple" id="skills" class="form-control select2 #error('a')
is-invalid
#enderror" onchange="myFunction()">
<option value="1" #if (old('a')=="1" ) {{ 'selected' }} #endif>Information and communication skills</option>
<option value="2" #if (old('a')=="2" ) {{ 'selected' }} #endif>Interpersonal skill</option>
<option value="3" #if (old('a')=="3" ) {{ 'selected' }} #endif>System management skills</option>
<option value="4" #if (old('a')=="4" ) {{ 'selected' }} #endif>Innovation skills</option>
<option value="5" #if (old('a')=="5" ) {{ 'selected' }} #endif>Others. Specify</option>
</select>
<small class="text-primary">If necessary, choose more than one option.</small>
#error('a') <span class="invalid-feedback" role="alert">{{ $message }}</span> #enderror
</div>
<div class="col-md-6" id="skillReason" {!! $errors->has('a_text') || old('a') == 5 ? '':' style="display: none"' !!} >
<div class="form-floating mb-3">
<textarea rows="2" class="form-control #error('a_text')#enderror" name="e2_10" id="skillReason" placeholder="Type here.."></textarea>
</div>
</div>
<div class="col-md-6">
<select name="b" id="b" class="form-control" onchange="myFunction2()">
<option value="" selected disabled>Select</option>
<option value="1" #if (old('b')=="1" ) {{ 'selected' }} #endif>Most of them match the requirements</option>
<option value="2" #if (old('b')=="2" ) {{ 'selected' }} #endif>Only some match the requirements</option>
<option value="3" #if (old('b')=="3" ) {{ 'selected' }} #endif>Other, specify</option>
</select>
#error('b') <span class="invalid-feedback" role="alert">{{ $message }}</span> #enderror
</div>
<div class="col-md-6 mt-2" {!! $errors->has('e3_5') || old('b') == 3 ? '':' style="display: none"' !!} >
<div class="form-floating mb-3">
<textarea rows="2" class="form-control" id="b_text" name="b_text" placeholder="Type here.."></textarea>
<label for="floatingInput" id="specify">Specify here..</label>
</div>
</div>
<div class="col-md-6">
<select name="c" id="graduatesPreference" class="form-control" onchange="myFunction3()">
<option value="" selected disabled>Select</option>
<option value="1" #if (old('c')=="1" ) {{ 'selected' }} #endif>Yes</option>
<option value="2" #if (old('c')=="2" ) {{ 'selected' }} #endif>No</option>
</select>
#error('c') <span class="invalid-feedback" role="alert">{{ $message }}</span> #enderror
</div>
<div class="col-md-6" id="preferenceReason" {!! $errors->has('c_text') || old('c') == 1 ? '':' style="display: none"' !!}>
<label for="">Provide the reason, why you have a preference for a specific university?</label>
<textarea name="c_text" id="" rows="3" class="form-control" placeholder="Provide the reason here ..."></textarea>
</div>
<div class="col-md-6">
<select name="d" id="qualification" class="form-control #error('d')is-invalid #enderror" onchange="myFunction4()">
<option value="" selected disabled>Select</option>
<option value="1" #if (old('d')=="1" ) {{ 'selected' }} #endif>Bachelor’s degree</option>
<option value="2" #if (old('d')=="2" ) {{ 'selected' }} #endif>Post-graduate</option>
<option value="3" #if (old('d')=="3" ) {{ 'selected' }} #endif>Other, specify</option>
</select>
#error('d') <span class="invalid-feedback" role="alert">{{ $message }}</span> #enderror
</div>
<div class="col-md-12" id="d_text" {!! $errors->has('d_text') || old('d') == 3 ? '':' style="display: none"' !!}>
<label for="">Explain why?</label>
<textarea name="d_text" id="d_text" rows="3" class="form-control" placeholder="Provide the reason here ..."></textarea>
</div>
////.............others fields like e,f,g,h, all have the same functionality like the above ones.
<div class="action-button d-flex justify-content-center bg-white pt-2 pb-2">
<button type="submit" class="btn btn-success">Save</button>
</div>
</div>
</form>
<script>
/// various function for onchange
myFunction()
myFunction2()
myFunction3()
myFunction4()
</script>
My question: what is the wright approach to handle the above scenario without writing 100's of if..elseif statements. Thanks in advance.

Answer 1

In form validation u have rules like required with or without, u can see more here
Little bit lower on the docs u can see Conditionally Adding Rules
So basically u will be doing same validation but without too much mess in your code.