JavaScript Array.prototype.map() Behavior with Sparse Arrays - Unexpected Undefined Values
I keep running into I've looked through the documentation and I'm still confused about I'm encountering unexpected behavior when using `Array.prototype.map()` on a sparse array in JavaScript. I assumed that `map()` would only iterate over the defined elements, but I'm seeing `undefined` values in the output that I didn't expect. Here's a snippet of my code: ```javascript const sparseArray = [1, , 3, , 5]; // Notice the missing elements const mappedArray = sparseArray.map(value => (value !== undefined ? value * 2 : 'N/A')); console.log(mappedArray); ``` When I run this, I get the output: ``` [ 2, undefined, 6, undefined, 10 ] ``` I thought `map()` should skip over the empty slots. However, the `undefined` values are being returned, which seems to be contradicting my expectations. I've also tried using `forEach()` to iterate through the array, and it behaves similarly: ```javascript const results = []; sparseArray.forEach(value => results.push(value !== undefined ? value * 2 : 'N/A')); console.log(results); ``` This yields: ``` [ 2, 'N/A', 6, 'N/A', 10 ] ``` Is there a way to make `map()` ignore the empty slots in a sparse array? Or is this just the intended behavior of `map()`? I'm using Node.js v14.17.0 and running this in a browser console as well. Any insights would be appreciated! This is part of a larger API I'm building. This is part of a larger REST API I'm building. Any ideas what could be causing this? I'd be grateful for any help.