Here is the reduce() function implementation:
function reduce(array, combine, start) {
let current = start;
for (let element of array) {
current = combine(current, element);
}
return current;
}
Now, I am tackling this question:
Utilize the reduce method along with the concat method to "flatten" an array of arrays into a single array that comprises all the elements of the original arrays.
Below is the solution:
let arrays = [[1, 2, 3], [4,5], [6]];
console.log(arrays.reduce((flat, current) => flat.concat(current), []));
// → [1, 2, 3, 4, 5, 6]
However, upon trying:
let arrays = [[1, 2, 3], [4, [79],5], [6]];
console.log(arrays.reduce((flat, current) => flat.concat(current), []));
The result is:
[1, 2, 3, 4, [79], 5, 6]
This indicates that the solution only handles flattening up to two nested arrays. But how does it work for arrays like [[1, 2, 3], [4,5], [6]]?
Considering the for loop in the reduce() function:
array = [1,4,6,[6,7],7,6,8,6];
for(element of array)
console.log(element);
// 146[6,7]7686
The for loop does not fetch values from nested arrays. How does the first solution work then, and how can we write a solution that works for any number of nested arrays using recursion?