如何根据给定的索引更新嵌套数组中的值并在javascript中返回原始数组？

Question

I have an index '3_1_0' and the following array:-

var fields = [
    {
        name: 'a'
    },
    {
        name: 'b'
    },
    {
        name: 'c'
    },
    {
        name: 'd',
        fields: [
            {
                name: 'd1'
            },
            {
                name: 'd2',
                fields: [
                    {
                        name: 'd2.1'
                    }
                ]
            }
        ]
    }
]

I need to extract the element from the above fields array based on the index. so 3_1_0 will extract following

{
    name: 'd2.1'
}

Update the value from d2.1 to some other value like 'new_d2.1' and attach the updated value at the same index in original fields array and return the updated fields array. How this can be done?

Answer 1

You can use Array.reduce to get the desired result. We start by splitting the index into an array, then reducing to get the result.

We'll use some Optional Chaining to ensure we'll return undefined if no value is found (say our index was '7_10_20').

Once we've found our object, we can set the required property.

 const fields = [ { name: 'a' }, { name: 'b' }, { name: 'c' }, { name: 'd', fields: [ { name: 'd1' }, { name: 'd2', fields: [ { name: 'd2.1' } ] } ] } ]; const index = '3_1_0' function setValue(fields, index, property, value) { const obj = index.split('_').reduce((acc, key) => { return acc?.[key] || acc?.fields?.[key]; }, fields); // Only update if we actually find anything if (obj) { obj[property] = value } } setValue(fields, '3_1_0', 'name', 'new_d2.1'); console.log("Fields:", fields);

Answer 2

 const data = [{ name: 'a' }, { name: 'b' }, { name: 'c' }, { name: 'd', fields: [ { name: 'd1' }, { name: 'd2', fields: [ { name: 'd2.1' } ] } ] } ]; let givenIdxs = "3_1_0"; let indexes = givenIdxs.split("_"); let result = data[indexes[0]]; for(let idx = 1; idx < indexes.length; idx++){ result = result.fields[indexes[idx]]; } console.log(result);