What is the output of the following code: [[0, 1], [2, 3]].reduce((acc, cur) => { return acc.concat(cur); }, [1, 2]);?

To determine the output of the provided code, let's analyze it step by step. This code uses the reduce method to concatenate arrays together.

1. The input to the reduce method is [[0, 1], [2, 3]], and it starts with an initial accumulator value of [1, 2].

2. During the first iteration, the accumulator is [1, 2], and the current value (cur) is [0, 1]. The concat method is called, which combines these two arrays:

• Result: [1, 2].concat([0, 1]) yields [1, 2, 0, 1].

3. In the second iteration, the accumulator is now [1, 2, 0, 1], and the current value is [2, 3]. Again, the concat method is used:

• Result: [1, 2, 0, 1].concat([2, 3]) yields [1, 2, 0, 1, 2, 3].

Therefore, the final output produced by the code is `[1