👀 Views: 169 💬 Answers: 1 📅 Created: 2025-07-22

javascript arrays splice nested-arrays JavaScript

I'm optimizing some code but I'm working with a nested array in JavaScript where I'm trying to remove specific items from the inner arrays based on a condition... I've encountered an unexpected behavior when using the `splice()` method. Here's the relevant part of my code: ```javascript let data = [ { name: 'Alice', scores: [90, 85, 88] }, { name: 'Bob', scores: [70, 75, 80] }, { name: 'Charlie', scores: [60, 65, 70] } ]; const removeLowScores = (threshold) => { data.forEach(student => { student.scores.forEach((score, index) => { if (score < threshold) { student.scores.splice(index, 1); } }); }); }; removeLowScores(80); console.log(data); ``` I'm trying to remove any scores below 80 from each student's scores array. However, after running this code, I noticed that not only are the low scores being removed, but I'm also skipping some scores. For instance, if a student has scores of `[70, 85, 90]`, after the function runs, their scores are incorrectly updated to `[85]`. I suspect this might be due to changing the length of the array while iterating over it. I tried using a different method, like creating a new array with `filter()`, but I really want to understand what's happening here. Is there a way to correctly remove the items without skipping any? Any advice would be appreciated! I'm working in a Ubuntu 22.04 environment. What's the best practice here? My development environment is Ubuntu 20.04. Hoping someone can shed some light on this. This is part of a larger CLI tool I'm building.