push to array index and reduce index having same key

Please help me merge array’s cities whereas the state is same and remove duplicate index. The expecting output is given below

Input array

[
    {
        "state": "delhi",
        "cities": "central delhi"
    },
    {
        "state": "jharkhand",
        "cities": "dumka"
    },
    {
        "state": "jharkhand",
        "cities": "deoghar"
    },
    {
        "state": "jharkhand",
        "cities": "jasidih"
    },
    {
        "state": "karnataka",
        "cities": "bail hongal"
    },
    {
        "state": "ladakh",
        "cities": "kargil"
    }
]

I have tried multiple code but adding this one as i am still trying to get my desired output

arr1.map((row, index) => ({
    itemLabel: arr1.state,
    itemValue: arr1.cities - arr2[index].cities
}))

Need this output

[
    {
        "state": "delhi",
        "cities": "central delhi"
    },
    {
        "state": "jharkhand",
        "cities": ["dumka","deoghar","jasidih"]
    },
    {
        "state": "karnataka",
        "cities": "bail hongal"
    },
    {
        "state": "ladakh",
        "cities": "kargil"
    }
]

>Solution :

You coudl group first and then map the citites.

const
    data = [{ state: "delhi", cities: "central delhi" }, { state: "jharkhand", cities: "dumka" }, { state: "jharkhand", cities: "deoghar" }, { state: "jharkhand", cities: "jasidih" }, { state: "karnataka", cities: "bail hongal" }, { state: "ladakh", cities: "kargil" }],
    result = Object
        .entries(Object.groupBy(data, ({ state }) => state))
        .map(([state, objects]) => ({ state, cities: objects.map(({ cities }) => cities) }));

console.log(result);