There is such an arbitrary array in which I need to find the sum of all numbers without using Array.isArray:
let arr = [[1, 2, 3, [4, 5, [6, 7]]], [8, [9, 10]]];
The solution should look something like this:
let arr = [[1, 2, 3, 4, 5], [6, 7, 8], [9, 10]];
for (let i = 0; i < arr.length; i++) {
for (let j = 0; j < arr[i].length; j++) {
console.log(arr[i][j]);
}
}
Could you please advise me on how to achieve this?
You could take Array#flat and Array#reduce the array or check the instance of the given value with instanceof operator.
function getSum1(array) {
return array.flat(Infinity).reduce((sum, value) => sum + value, 0);
}
function getSum2(array) {
let sum = 0;
for (const value of array) {
sum += value instanceof Array
? getSum2(value)
: value
}
return sum;
}
let array = [[1, 2, 3, [4, 5, [6, 7]]], [8, [9, 10]]];
console.log(getSum1(array));
console.log(getSum2(array));Use flat and reduce methods to accomplish this.
let arr = [[1, 2,
3, [4, 5, [6, 7]]],
[8, [9, 10]]];
arr.flat(Infinity).reduce((a, b) => a + b, 0)
Flat: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/flat
Reduce: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/reduce
you use lodash for this:
var _ = require("lodash");
var arr = [[1, 2, 3, [4, 5, [6, 7]]], [8, [9, 10]]];
flatArr = _.flattenDeep(arr);
flatArr.reduce((sum, value) => sum + value, 0);