How do I use .reduce() to take a multi-layered array and return a single layer array from scratch?

Answer 1

Thanks a lot Ben Bright , I will give it a read 👍

Answer 2

It all depends on how you want the results to be, but for flat out all arrays into a single layered, you can implement it like this;

say we have this 3x3 multi-dimensional array:

// array
const grades = [
[1, 2, 3],
[4, 5, 6],
[7, 8, 9]
];

// reduce
const output = grades.reduce((accum, item) => {
accum = [...accum, ...item];
return accum;
}, []);

// result
console.log(output) //=> [1, 2, 3, 4, 5, 6, 7, 8, 9]

Hope it helps, happy coding!

Answer 3

Ipang please read from here it's well explained:

// reduce
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/Reduce

// spread operator
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_syntax

if you still don't get it, send me a chat.

Hope it helps, happy coding!

Answer 4

Well this is embarrassing 😁, but I don't understand what happens in that section of reduce, the part that's troubling me understanding is with the ...

`accum[...accum, ...item]`

and the square bracket in the ending ...

`},[]);` <- this square bracket

Ben Bright ,I need enlightenment with that 😁

Thanks,

Answer 5

//array
const arra = [[1,2],[3,4],[4,5,6]];

//newArray
const newArr = arra.reduce((a,b)=>{
for(i=0;i<b.length;i++)
{
a.push(b[i]); // pushing the elements into accumulator
}
return a; //returning the accumulator for every iteration
},[])
console.log(newArr);

Hope this helps!