LookupComponent.cmp

<aura:component controller="LookupSearchComponentController">
    <aura:attribute name="objectName" type="String" default="Account"/>
    <aura:attribute name="fieldName" type="String" default="Name"/>
    <aura:attribute name="selectRecordId" type="String"/>
    <aura:attribute name="selectRecordName" type="String"/>
    <aura:attribute name="Label" type="String"/>
    <aura:attribute name="searchRecords" type="List"/>
    <aura:attribute name="required" type="Boolean" default="false"/>
    <aura:attribute name="iconName" type="String" default="action:new_account"/>
    <aura:attribute name="LoadingText" type="Boolean" default="false"/>
    
    <div>
        <div class="slds-form-element">
            
            <div class="slds-form-element__control">
                <div class="slds-combobox_container">
                    
                    <div class="slds-combobox slds-dropdown-trigger slds-dropdown-trigger_click" aura:id="resultBox" aria-expanded="false" aria-haspopup="listbox" role="combobox">
                        <div class="slds-form-element__control slds-input-has-icon slds-input-has-icon slds-input-has-icon_left-right" role="none">
                            
                            <aura:if isTrue="{!!empty(v.selectRecordId)}">
                                <span class="slds-icon_container slds-icon-utility-search slds-input__icon iconheight">
                                    <lightning:icon class="slds-icon slds-icon slds-icon_small slds-icon-text-default" iconName="{!v.iconName}" size="x-small" alternativeText="icon" />
                                </span> 
                            </aura:if>
                            <lightning:input required="{!v.required}" aura:id="userinput" label="{!v.Label}" name="searchText" onchange="{!c.searchField}" value="{!v.selectRecordName}" class="leftspace"/> 
                            <aura:if isTrue="{!empty(v.selectRecordId)}">
                                <span class="slds-icon_container slds-icon-utility-search slds-input__icon slds-input__icon_right iconheight">
                                    <lightning:icon class="slds-icon slds-icon slds-icon_small slds-icon-text-default" iconName="utility:search" size="x-small" alternativeText="icon" />
                                </span> 
                                <aura:set attribute="else">
                                    <button class="slds-input__icon slds-input__icon_right slds-button slds-button_icon iconheight" onclick="{!c.resetData}">
                                        <lightning:icon class="slds-icon slds-icon slds-icon_small slds-icon-text-default" iconName="utility:clear" size="x-small" alternativeText="icon" />
                                        <span class="slds-assistive-text">Clear</span></button>
                                </aura:set>
                            </aura:if>
                        </div>
                        
                        <!-- Second part display result -->
                        <div id="listbox-id-1" class="slds-dropdown slds-dropdown_length-with-icon-7 slds-dropdown_fluid" role="listbox">
                            <ul class="slds-listbox slds-listbox_vertical" role="presentation">
                                <aura:iteration items="{!v.searchRecords}" var="serecord" indexVar="hdtv">
                                    <li role="presentation" class="slds-listbox__item">
                                        
                                        <div id="{!serecord.recId}" data-name="{!serecord.recName}" onclick="{!c.setSelectedRecord}" class="slds-media slds-listbox__option slds-listbox__option_entity slds-listbox__option_has-meta" role="option">
                                            <span class="slds-media__figure">
                                                <span class="slds-icon_container slds-icon-standard-account">
                                                    <lightning:icon iconName="{!v.iconName}" class="slds-icon slds-icon slds-icon_small slds-icon-text-default" size="x-small"/>
                                                </span>
                                            </span>
                                            <span class="slds-media__body">
                                                <span class="slds-listbox__option-text slds-listbox__option-text_entity">{!serecord.recName}</span>
                                                <span class="slds-listbox__option-meta slds-listbox__option-meta_entity">{!v.objectName} • {!serecord.recName}</span>
                                            </span>
                                        </div>
                                    </li>
                                </aura:iteration>
                                <aura:if isTrue="{!and(v.searchRecords.length == 0 , !v.LoadingText)}">
                                    No result found.
                                </aura:if>
                                <aura:if isTrue="{!v.LoadingText}">
                                    Loading...
                                </aura:if>
                            </ul>
                        </div>
                    </div>
                </div>
            </div>
        </div>
    </div>
    
</aura:component>

LookupComponent.CSS

.THIS .slds-leftpad{
	padding-left: 2rem;
}
.THIS .iconheight{
    top: 65%;
}

.THIS .leftspace input {
    padding-left:2rem;
}

LookupComponent.JS

({
    searchField : function(component, event, helper) {
        var currentText = event.getSource().get("v.value");
        var resultBox = component.find('resultBox');
        component.set("v.LoadingText", true);
        if(currentText.length > 0) {
            $A.util.addClass(resultBox, 'slds-is-open');
        }
        else {
            $A.util.removeClass(resultBox, 'slds-is-open');
        }
        var action = component.get("c.getResults");
        action.setParams({
            "ObjectName" : component.get("v.objectName"),
            "fieldName" : component.get("v.fieldName"),
            "value" : currentText
        });
        
        action.setCallback(this, function(response){
            var STATE = response.getState();
            if(STATE === "SUCCESS") {
                component.set("v.searchRecords", response.getReturnValue());
                if(component.get("v.searchRecords").length == 0) {
                    console.log('000000');
                }
            }
            else if (state === "ERROR") {
                var errors = response.getError();
                if (errors) {
                    if (errors[0] && errors[0].message) {
                        console.log("Error message: " + 
                                    errors[0].message);
                    }
                } else {
                    console.log("Unknown error");
                }
            }
            component.set("v.LoadingText", false);
        });
        
        $A.enqueueAction(action);
    },
    
    setSelectedRecord : function(component, event, helper) {
        var currentText = event.currentTarget.id;
        var resultBox = component.find('resultBox');
        $A.util.removeClass(resultBox, 'slds-is-open');
        //component.set("v.selectRecordName", currentText);
        component.set("v.selectRecordName", event.currentTarget.dataset.name);
        component.set("v.selectRecordId", currentText);
        component.find('userinput').set("v.readonly", true);
    }, 
    
    resetData : function(component, event, helper) {
        component.set("v.selectRecordName", "");
        component.set("v.selectRecordId", "");
        component.find('userinput').set("v.readonly", false);
    }
})

LookupSearchComponentController

public class LookupSearchComponentController {
    
    @AuraEnabled
    public static List<SObJectResult> getResults(String ObjectName, String fieldName, String value) {
        List<SObJectResult> sObjectResultList = new List<SObJectResult>();
        for(sObject so : Database.Query('Select Id,'+fieldName+' FROM '+ObjectName+' WHERE '+fieldName+' LIKE \'%' + value + '%\'')) {
            String fieldvalue = (String)so.get(fieldName);
            sObjectResultList.add(new SObjectResult(fieldvalue, so.Id));
        }
        
        return sObjectResultList;
    }
    
    public class SObJectResult {
        @AuraEnabled
        public String recName;
        @AuraEnabled
        public Id recId;
        
        public SObJectResult(String recNameTemp, Id recIdTemp) {
            recName = recNameTemp;
            recId = recIdTemp;
        }
    }
}