How to access aura:id value in init method of salesforce lightning

Question

When I click on Edit Button

When I have changed value of "Case Type" picklist, Request Detail section is to appear on change of picklist value

I want to show this section on load of this edit page. I am using following code.

<aura:handler name="init" action="{!c.doInit}" value="{!this}"/>

 <lightning:inputField fieldName="Type" aura:id ="caseTypeId" onchange="{!c.caseTypeChange}"/> 

<aura:if isTrue="{!v.caseTypeValue =='Requests'}"> 
                     <br/>
                      <h3 class="slds-section-title--divider">Request Details</h3>
                      <div class="slds-grid">
                        <div class="slds-col">
                          <span>
                               <lightning:inputField fieldName="Description" />
                          </span>
                        </div>
                        &nbsp;&nbsp;
                        <div class="slds-col">
                          <span>
                               <lightning:inputField fieldName="Subject" />
                          </span>
                        </div>       
                    </div>
</aura:if>

component code

doInit: function(component, event, helper) {
    //Edit Case
    helper.caseTypeChangeHelperFun(component, event);                        
},  caseTypeChange : function(component, event, helper) {        
   helper.caseTypeChangeHelperFun(component, event);
},

Helper Code

 caseTypeChangeHelperFun: function(component, event){               
         var caseTypeIdValue=component.find("caseTypeId").get("v.value");  
         component.set("v.caseTypeValue", caseTypeIdValue);      
         console.log('--caseTypeIdValue---'+caseTypeIdValue); 
    },

Problem

1. When I click on the 'case Type' pick list "request detail" section is showing perfectly.

2. When I load the "Edit" page and if value is selected as "request" the related section is not showing. This is the problem.

Answer 1

You can access aura:id value like this :

 var caseTypeidValue=component.find("caseTypeId").get("v.value"); //here you will the value

Answer 2

By this way, you will get value in init method.

Component: 
Please add this in lightning component 
<lightning:inputField fieldName="Type" aura:id ="caseTypeId" id="caseTypeId1" value="10"/>   
<aura:handler name="init" value="{!this}" action="{!c.doInit}"/>

Controller:
({
    doInit: function(cmp) {
        var caseTypeidValue=cmp.find("caseTypeId").get("v.value"); 
    }
})