I want to get array of multiple emp for particular Manager

I have a data where each emp has manager, i’m trying to get an array with emp with perticular manager. for ex: Manager1 with array of all his emp and Manager2 with all his emp. i have pasted a sample out.how can i get that?

const response = [
    {
        "emp":{
            "firstName":"Abhi"
        },
        "manager":{
            "firstName":"Ashok"
        }
    },
    {
        "emp":{
            "firstName":"Lokesh"
        },
        "manager":{
            "firstName":"Ashok"
        }
    },
    {
        "emp":{
            "firstName":"Harish"
        },
        "manager":{
            "firstName":"Ashok"
        }
    },
    {
        "emp":{
            "firstName":"Kaushik"
        },
        "manager":{
            "firstName":"Sunil"
        }
    },
]
            
            

Sample output i need:

[
    {
        "manager":"Ashok",
        "emp":[
            {
                "firstName":"Abhi"
            },
            {
                "firstName":"Lokesh"
            },
            {
                "firstName":"Harish"
            }
        ]
    },
    {
        "manager":"Sunil",
        "emp":[
            {
                "firstName":"Kaushik"
            }
        ]
    }
]