Question

How to create function that flatten nested array of any depth in JavaScript

Answer 1

function DeepFlatten(arr) {     
   return arr.reduce((f, val) => Array.isArray(val) ? 
   f.concat(DeepFlatten(val)) : f.concat(val), []);  
}  

const arr = [[1,2], [3,[4,5],[12, 13, [100, 200], 14, 15], 6], [7], [8,9,10]];

const arr_flat = DeepFlatten(arr);

for (let i = 0; i < arr_flat.length; i++)    
    console.log(arr_flat[i]);



/*
run:

1
2
3
4
5
12
13
100
200
14
15
6
7
8
9
10

*/

 

70+ SQL courses for beginners and professionals

Answer 2

function DeepFlatten(arr) {     
   return arr.reduce((f, val) => Array.isArray(val) ? 
   f.concat(DeepFlatten(val)) : f.concat(val), []);  
}  

const arr = [1, [2, 'java', 3, [4, 'script', [5, 6] ] ], 7, [8, [9, true, false] ] ];

const arr_flat = DeepFlatten(arr);

for (let i = 0; i < arr_flat.length; i++)    
    console.log(arr_flat[i]);




/*
run:

1
2
"java"
3
4
"script"
5
6
7
8
9
true
false

*/

 

70+ SQL courses for beginners and professionals