Which two-dimensional array to get one-dimensional is the shortest way?

Question

I have this array

[[1,2,3][4,5,6][7,8,9]]

how to get from this such

[1,2,3,4,5,6,7,8,9]

without using Array.map

Answer 1

You can do:

const data = [[1, 2, 3], [4, 5, 6], [7, 8, 9]];
const result = data.reduce((a, c) => a.concat(c), []);

console.log(result);

Answer 2

use Array#flatMap method to flatten returned arrays.

let data = [
  [1, 2, 3],[4, 5, 6],[7, 8, 9]
];


console.log(data.flatMap(a => a))

---

Or use Array#reduce method to iterate and reduce into a single array.

let data = [
  [1, 2, 3],[4, 5, 6],[7, 8, 9]
];


console.log(data.reduce((arr, a) => [...arr, ...a]), [])

Or even you can use the built-in Array#flat method which is created for this purpose. If you want to fatten a nested array then specify the depth argument by default it would be 1.

let data = [
  [1, 2, 3],[4, 5, 6],[7, 8, 9]
];


console.log(data.flat())

Answer 3

You can use array flat

let k = [
  [1, 2, 3],
  [4, 5, 6],
  [7, 8, 9]
]

let m = k.flat();
console.log(m)

Answer 4

You can use flat()

const arr = [[1,2,3],[4,5,6],[7,8,9]]
console.log(arr.flat())

If you don't want to use flat() then you can use push() and spread operator.

const arr = [[1,2,3],[4,5,6],[7,8,9]]
const res = [];
arr.forEach(x => res.push(...x))
console.log(res)

Answer 5

You can use Array​.prototype​.flat()

The flat() method creates a new array with all sub-array elements concatenated into it recursively up to the specified depth.

var arr = [[1,2,3],[4,5,6],[7,8,9]];
var res = arr.flat();
console.log(res);