Iterate nested array of objects, find id and update object matching the id

Question

I have below input as follows. Its an array of objects and each object has states which is also a array of objects. i want to append details inside the states object when the state id matches with the id mentioned below. ie 82175746

const input = 
[
    {
        "country": { "id": 87745195, "action": "Analyze" },
        "states": [
            { "id": 83589582, "action": "Verify" },
            { "id": 87335656, "action": "Analyze" }
        ]
    },
    {
        "country": { "id": 83861166, "action": "Verify" },
        "states": [
            { "id": 82175746, "action": "Closed" },
            { "id": 78745158, "action": "Closed" }
        ]
    }
]


const details = { "totalOpenRadars": 1, "totalClosedRadars": 1 }

const id = 82175746

And this is the result i am trying to achieve. Please note that id of 82175746 is compared with all the state ids. once a match is found, details mentioned above is appended as shown below to the matched object.

const result = 
[
    {
        "country": { "id": 87745195, "action": "Analyze" },
        "states": [
            { "id": 83589582, "action": "Verify" },
            { "id": 87335656, "action": "Analyze" }
        ]
    },
    {
        "country": { "id": 83861166, "action": "Verify" },
        "states": [
            { "id": 82175746, "action": "Closed", "details": { "totalOpenRadars": 1, "totalClosedRadars": 1 } },
            { "id": 78745158, "action": "Closed" }
        ]
    }
]

In order to achieve this, I tried this way but I am not able to get the result properly. Can someone please let me know where I went wrong

const result  = input.forEach((element) => {
    element.states.forEach((state) => {
        if(state.id === id) {
            state.details = details
        }

    });
});

Answer 1

Array.forEach always returns undefined , so result will always be undefined . If you look at input after your operation, it does contain your details as you specified.

Alternatively, you could spread input into a new array called result and perform your loop on result instead if you intend to keep input the same.

 const input = [ { "country": { "id": 87745195, "action": "Analyze" }, "states": [ { "id": 83589582, "action": "Verify" }, { "id": 87335656, "action": "Analyze" } ] }, { "country": { "id": 83861166, "action": "Verify" }, "states": [ { "id": 82175746, "action": "Closed" }, { "id": 78745158, "action": "Closed" } ] } ] const details = { "totalOpenRadars": 1, "totalClosedRadars": 1 } const id = 82175746 input.forEach((element) => { element.states.forEach((state) => { if(state.id === id) { state.details = details } }); }); console.log(input);

Answer 2

You can use Array.prototype.map() :

 const input = [{"country": { "id": 87745195, "action": "Analyze" },"states": [{ "id": 83589582, "action": "Verify" },{ "id": 87335656, "action": "Analyze" }]},{"country": { "id": 83861166, "action": "Verify" },"states": [{ "id": 82175746, "action": "Closed" },{ "id": 78745158, "action": "Closed" }]}] const details = { "totalOpenRadars": 1, "totalClosedRadars": 1 } const id = 82175746 const result = input.map(item => item.states.map(state => ({ ...state, ...(state.id === id ? { details } : {}) }))) console.log(result)

Answer 3

this should be do it

 const appendDetails = (data, id, details) => data.map(d => { return { ...d, states: d.states.map(s => { if(s.id !== id){ return s } return { ...s, details } }) } }) const input = [ { "country": { "id": 87745195, "action": "Analyze" }, "states": [ { "id": 83589582, "action": "Verify" }, { "id": 87335656, "action": "Analyze" } ] }, { "country": { "id": 83861166, "action": "Verify" }, "states": [ { "id": 82175746, "action": "Closed" }, { "id": 78745158, "action": "Closed" } ] } ] const details = { "totalOpenRadars": 1, "totalClosedRadars": 1 } const id = 82175746 console.log(appendDetails(input, id, details))