👀 Views: 1 💬 Answers: 1 📅 Created: 2025-06-12

javascript node.js arrays JavaScript

I'm updating my dependencies and I tried several approaches but none seem to work. I tried several approaches but none seem to work. I'm working on a project and hit a roadblock... I'm working on a Node.js application where I need to filter out duplicate objects from an array based on a unique key, specifically the `id` property. I have an array of objects that looks like this: ```javascript const items = [ { id: 1, name: 'Item A' }, { id: 2, name: 'Item B' }, { id: 1, name: 'Item A Duplicate' }, { id: 3, name: 'Item C' } ]; ``` I want to end up with an array that only contains unique items based on their `id` values. However, when I try to use `Array.prototype.filter`, I find that my approach isn't working as expected. Here's what I attempted: ```javascript const uniqueItems = items.filter((item, index, self) => index === self.findIndex((t) => (t.id === item.id)) ); ``` This code seems okay, but I end up with an unexpected result where the duplicate object with `id: 1` is still included in the final array. The output I get is: ```javascript [ { id: 1, name: 'Item A' }, { id: 2, name: 'Item B' }, { id: 1, name: 'Item A Duplicate' }, { id: 3, name: 'Item C' } ] ``` I also considered using the `reduce` function, but I’m not sure how to properly accumulate unique items without losing references to the original objects. Here’s my attempt with `reduce`: ```javascript const uniqueItems = items.reduce((acc, current) => { const x = acc.find(item => item.id === current.id); if (!x) { return acc.concat([current]); } else { return acc; } }, []); ``` While this seems more logical, it amends the approach by still retaining duplicates. I don’t see any behavior messages, but I'm clearly not achieving my goal. Can anyone suggest an efficient way to filter out duplicates from the array based on the unique `id` property? Any best practices for this scenario would also be greatly appreciated! Has anyone else encountered this? This is part of a larger application I'm building. Is there a better approach? Is there a better approach? I'm using Javascript 3.10 in this project. What are your experiences with this? I'd really appreciate any guidance on this.