# Sum of array elements with recursion in JavaScript

Let's find the sum of the primitive elements of our array:

`function func(arr) { let sum = 0; for (let elem of arr) { if (typeof elem == 'object') { sum += func(elem); } else { sum += elem; } } return sum; } console.log(func([1, [2, 7, 8], [3, 4, [5, [6, 7]]]]));`

A multidimensional object of arbitrary nesting level is given, for example, such as:

`{a: 1, b: {c: 2, d: 3, e: 4}, f: {g: 5, j: 6, k: {l: 7, m: {n: 8, o: 9}}}}`

Use recursion to find the sum of the elements of this object.

A multidimensional array of arbitrary nesting level, containing strings inside, is given, for example, such as:

`['a', ['b', 'c', 'd'], ['e', 'f', ['g', ['j', 'k']]]]`

Use recursion to merge the elements of this array into one string:

`'abcdefgjk'`
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