@wire decorator sending 'null' value to Apex in LWC

Question

I have 2 methods in my apex class one is fetching the record and another one is for updating

public with sharing class UpdateCaseRecord {

@AuraEnabled(cacheable=true)
public static Case fetchCase(Id caseId){ 
    return [SELECT Id,EngineeringReqNumber__c FROM Case where id=:caseId];
}

@AuraEnabled
public static void updateCase(Case con, Id recTypId){
    System.debug(con);
    system.debug('============>'+recTypId);
    update con;
  }
}

So

I have to pass 2 independent record Id to both the method. As you can see in updateCase method I am passing recTypId which I decorated in @wire but its giving me null value

import getCaseRec from "@salesforce/apex/UpdateCaseRecord.fetchCase";
import updateCaseRecord from '@salesforce/apex/UpdateCaseRecord.updateCase';

@api selectedValue;
@api recordId;
 
@wire (getCaseRec , { caseId: '$recordId'})       
fetchCase( resp){
       this.wiredCase = resp;
       this.realFormData = {... this.wiredCase.data};
}

@wire (updateCaseRecord , { recTypId: '$selectedValue'})
saveRecord(event){
    updateCaseRecord({con : this.realFormData}).then(()=>{
        console.log('Refresh Apex called');
        refreshApex(this.wiredCase);
    });

}

Note

In above code @api selectedValue; contains the Id of RecordTypes, It will pass the dynamic id value of that RecordType based upon the value selected from the dropdown

Answer 1

Is this a combobox where the different values can be selected? Do you have a function that is handling the change event of the selectedValue? Have you tried using console.log to check if selectedValue is null before it is being sent to apex? Also it could be worth trying {recTypId: this.selectedValue} instead of {recTypId: '$selectedValue'} Also your apex method is expecting 2 arguments. You are only sending 1 argument which might be causing unexpected behavior.

Handling the change event:

handleChange(event){
    this.selectedValue = event.detail.value;
    console.log(event.detail.value);
}

Calling apex method:

@wire (updateCaseRecord , { recTypId: this.selectedValue})
saveRecord(event){
    updateCaseRecord({con : this.realFormData}).then(()=>{
        console.log('Refresh Apex called');
        refreshApex(this.wiredCase);
    });

}

Edit: you should refactor to invoke the the update imperatively. Here is some info on how to do this and the situations when @wire should and should not be used. https://developer.salesforce.com/docs/component-library/documentation/en/lwc/lwc.apex