How to access map value in lightning component

Scenario: I have to create a picklist in Lightning, the values of which will be fetched from an already defined custom setting. The Apex method will be returning a map of values.

Define a method in Apex class SampleController which will return a map of values.

@AuraEnabled
public static Map<String, String> getselectOptions() {
    Map<String, CustomSettingName__c> values = CustomSettingName__c.getAll();
    Map<String, String> options = new Map<String, String>();
    
    for (String key: values.keyset()) {
        options.put(key, values.get(key).CustomSetting_Column__c);
    }
    return options;
}

Now in client side controller, create a new array optionsList. Add the values to this new array from the response object returned.

var optionsList = [];
for (var key in response) {
    if (response.hasOwnProperty(key)) {
        optionsList.push({value: key, label: response[key]});
    }
};
component.set('v.optionsList', optionsList);

Once the array is populated with the values, using aura:iteration tag populate the picklist values as below:

<aura:component controller="SampleController">
    
    <aura:attribute name="optionsList" type="List"/>

    <lightning:select name="selectItem" label="text" onchange="{!c.checkOptionValue}" value="{!v.partnerTypeSelected}" >
        <aura:iteration items="{!v.optionsList}" var="option">
            <option value="{!option.value}" text="{!option.label}" 
                    selected="{!option.selected}">
            </option>
        </aura:iteration>
    </lightning:select>
    
</aura:component>