# Sort in multi-dimensional arrays in JavaScript

Suppose, we have the following array of arrays −

const arr = [
["A","F","A","H","F","F"],
["F","A","A","F","F","H"]
];

We are required to write a JavaScript function that takes in one such array.

The function should sort all the subarrays of the given array internally according to these rules −

• If the elements are not either "A" or "F", they should maintain their position
• If the element is either of "A" or "F", they should be sorted alphabetically

Therefore, the final output for the above array should look like −

const output = [ ["A","A","A","H","A","F"],
["F","F","F","F","F","H"]
];

Note that elements from subarrays can change their arrays if the sorting algorithm makes them to do so.

## Example

const arr = [
["A","F","A","H","F","F"],
["F","A","A","F","F","H"]
];
const customSort = (arr = []) => {
const order = [].concat(...arr.slice()),
res = []; order.forEach((el, ind) => {
if (el === 'A') {
const fIndex = order.indexOf('F');
if (fIndex < ind){
order[fIndex] = 'A'; order[ind] = 'F';
};
};
})
arr.forEach(el => res.push(order.splice(0, el.length)))
return res;
}
console.log(customSort(arr));

## Output

And the output in the console will be −

[ [ 'A', 'A', 'A', 'H', 'A', 'F' ], [ 'F', 'F', 'F', 'F', 'F', 'H' ] ]

Updated on: 21-Nov-2020

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