Group array values in group of 3 objects in each array using underscore.js

Question

Below is an array in which I have to group 3 values in each object:

var xyz = {"name": ["hi","hello","when","test","then","that","now"]};

Output should be below array:

[["hi","hello","when"],["test","then","that"],["now"]]

Answer 1

Here's a short and simple solution abusing the fact that .push always returns 1 (and 1 == true):

const arr = [0, 1, 2, 3, 4, 5, 6]
const n = 3

arr.reduce((r, e, i) =>
    (i % n ? r[r.length - 1].push(e) : r.push([e])) && r
, []); // => [[0, 1, 2], [3, 4, 5], [6]]

Plus, this one requires no libraries, in case someone is looking for a one-liner pure-JS solution.

Answer 2

Pure javascript code:

function groupArr(data, n) {
    var group = [];
    for (var i = 0, j = 0; i < data.length; i++) {
        if (i >= n && i % n === 0)
            j++;
        group[j] = group[j] || [];
        group[j].push(data[i])
    }
    return group;
}

groupArr([1,2,3,4,5,6,7,8,9,10,11,12], 3);

Answer 3

This can be covered by lodash _.chunk:

var xyz = {"name": ["hi","hello","when","test","then","that","now"]},size = 3;
console.log(_.chunk(xyz.name, size));

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.11/lodash.js"></script>