数组拆分为 2 和 map 对应的对象并将它们放入结果数组中

Question

I have an array of array of objects similar to this:

arr = [{
    val: 1,
    ts: 123
}, {
    val: 2,
    ts: 125
}, {
    val: 3,
    ts: 120
}, {
    val: 4,
    ts: 113
}, {
    val: 5,
    ts: 117
}, {
    val1: 6,
    ts: 143
}, {
    val1: 7,
    ts: 193
}, {
    val1: 8,
    ts: 187
}, {
    val1: 9,
    ts: 115
}, {
    val1: 10,
    ts: 116
}]

The length of the array is always an even number. Now basically I'd like to split them in 2 halves

split1 = [{ val:1},  {val :2}, ......{val:5}]
split2 = [{val1:6},{val1:7},.......{val1:10}]

Now I have to map over these arrays and combine their fields(first item of array1 with first item of array2 and so on) into one single object and add an extra id to it such that result will look like

final = [{val:1, val1:6 , id:1} , {val:2, val1:7,id:3} , {val:3, val1:8,id:3},{val:4, val1:9,id:4},{val: 5, val1:10, id:5}]

This should hold for all arrays of even length and I want to make it a dynamic one. Keys will never be repeated inside source array

What I have tried is:

var res= a.splice(0, arr.length/2);
var c = a.map((val, ind) => { {val, res[ind]} })

Can someone guide here?

Answer 1

You can try this solution

 const arr = [{ val: 1},{val: 2},{val: 3}, {val: 4}, {val:5},{ val1: 6},{val1: 7},{val1: 8}, {val1: 9}, {val1:10}] const split = arr => [arr.slice(0, arr.length/2), arr.slice(arr.length/2, arr.length)] const splitedArr = split(arr); const merge = arr => { const merged = [] for(let i = 0; i < arr[0].length; i++){ let newObj = {...arr[0][i], ...arr[1][i], id:(i+1)} merged.push(newObj); } return merged; } const mergedArr = merge(splitedArr); console.log(mergedArr);

Answer 2

I have tried

var res= a.splice(0, arr.length/2); var c = a.map((val, ind) => { {val, res[ind]} })

You're quite close. To make the map callback syntactically valid and create the desired object, it should be

var res = a.splice(0, arr.length/2);
var c = a.map((val, ind) => {
    return {val: val.val, val1: res[ind].val1, id: ind+1};
})

or

var c = a.map((val, ind) => {
    return Object.assign({id: ind+1}, val, res[ind]);
})

Answer 3

You're quite close, some minor fixes

1. wrap map function implicit return with () instead of {}
2. for adding computed value you need to assign key name explicitly
3. need to destructure val or need to access val.val

 const arr = [{ val: 1}, {val: 2}, {val: 3}, {val: 4}, {val: 5}, {val1: 6}, {val1: 7}, {val1: 8}, {val1: 9}, {val1: 10}]; const firstHalf = arr.slice(0, arr.length / 2); const secondHalf = arr.slice(arr.length / 2); const final = secondHalf.map((val, ind) => ({...val, ...firstHalf[ind], id: ind, })) console.log(final);