Inconsistent Results When Using Array.prototype.reduce to Flatten Nested Arrays in JavaScript
I'm having a hard time understanding I'm not sure how to approach I'm writing unit tests and I'm refactoring my project and I've been struggling with this for a few days now and could really use some help... I'm working with an scenario when trying to flatten an array of nested arrays using the `Array.prototype.reduce` method in JavaScript. My input array has inconsistent nesting levels, and while the approach works for most cases, I'm working with unexpected results in specific scenarios. For example, given the input `[[1, 2], [3, [4, 5]], 6]`, I expect the output to be `[1, 2, 3, 4, 5, 6]`. However, my current implementation only flattens one level deep and doesn't handle the deeper nested arrays correctly. Here’s the code I’ve written: ```javascript const flattenArray = (arr) => { return arr.reduce((acc, val) => { return acc.concat(val); }, []); }; const nestedArray = [[1, 2], [3, [4, 5]], 6]; const flattened = flattenArray(nestedArray); console.log(flattened); ``` When I run this code, the output is `[1, 2, 3, [4, 5], 6]`, which is not what I want. I've considered using recursion to handle arbitrary depth, but I’m unsure how to implement that effectively without making the code overly complex. I’m also looking to ensure that the performance remains optimal, especially with larger datasets. What would be the best approach to flatten this array completely, and are there any common pitfalls to avoid while doing this? My development environment is Ubuntu. What's the best practice here? Any help would be greatly appreciated! Thanks for any help you can provide! I'm using Javascript stable in this project. I've been using Javascript for about a year now. Has anyone dealt with something similar? Any examples would be super helpful.