How do I get Field values of a form on lightning:button click?

Question

I have a form that has multiple fields in it. I want the values of those fields when I click on the "Apply" button. I am creating a filter, so I need the values and the field name in a string so I can change my SOQL Query accordingly. I don't know how to go about the controller code. Do I use component.find or something else? I'm not sure. All the fields are created dynamically. So I can't use aura:id for them because that causes issues apparently. Is there a way to go about it?

Component Code:

      <form aura:id ="filterForm">
            <div class="slds-grid slds-gutters">
                <div class="slds-col">
                    <aura:iteration items="{!v.filterList}" var="val">
                        <aura:if isTrue="{!val.type == 'PICKLIST'}">
                            {!val.pickListValue}
                            <lightning:select label="{!val.label}"><!--GET FROM CUSTOM LABEL-->
                                    <option text="None" value="None"/>
                                <aura:iteration items="{!val.pickListValue}" var="val1">
                                    <option text="{!val1.label}" value="{!val1.value}"/>
                                </aura:iteration>
                            </lightning:select>
                            <aura:set attribute="else">
                                <lightning:input label="{!val.label}" value = "{!v.collStrat}"/>
                            </aura:set>
                        </aura:if>
                    </aura:iteration>
                    <lightning:button class="slds-m-top_small" label="Cancel" />
                    <lightning:button onclick="{!c.handleSubmit}" class="slds-m-top_small" label="Apply" />
                                               </div>
                <div class="slds-col">
                </div>
            </div>
        </form>     

Controller Code:

handleSubmit: function(component, event, helper) {
        component.set('v.filterOpen',false);
        var mainForm = component.find("filterForm");
        console.log(mainForm);
       // var fields = event.getParam('fields');

    },

Answer 1

In theory, you should be able to use the values stored in the filterList attribute. You just need a few minor adjustments:

<lightning:select label="{!val.label}" value="{!val.selectedValue}"><!--GET FROM CUSTOM LABEL-->

And:

<lightning:input label="{!val.label}" value="{!val.selectedValue}"/>

By binding "value" to val, the iterator, those values will be stored in filterList, which you can then extract:

handleSubmit: function(component, event, helper) {
   var data = component.get("v.filterList").map(filter=>filter.selectedValue);

You can also use aura:id if you prefer:

<lightning:select label="{!val.label}" aura:id="inputs"><!--GET FROM CUSTOM LABEL-->

...

<lightning:input label="{!val.label}" aura:id="inputs" />

...

handleSubmit: function(component, event, helper) {
    var data = component.find("inputs").map(input=>input.get("v.value"));

These are the two most common techniques; you could also use event handlers to store the changes made somewhere, etc.