sachasi / last_item

⚡ Get the last N items of an array or just the last one, fast!

Last Item

Get the last N items of an array or just the last one, faster than Array.prototype.slice/Array.prototype.at.

Usage

The API is the same on all this platforms ✔️

Deno 🦕

import { lastItem } from "https://deno.land/x/last_item/mod.ts";

const numbers = [1, 2, 3, 4, 5];

lastItem(numbers); //=> 5

lastItem(numbers, 3); //=> [3, 4 , 5]

Node.js 🐢🚀

import { lastItem } from "@ultirequiem/last-item";

Browser 🌐

You can use any CDN 🔥

Eg 👉 ESM ↔️ SkyPack 🆚 Script Tag ↔️ JSDelivr

Alternatives

This is a utility module, which focuses on being faster than its native counterparts and similar modules.

In the vast majority of cases you should prefer Array.prototype.slice or Array.prototype.at if performance is not an issue.

One of the biggest advantages of this module is also that it is packaged to be easy to use in various environments such as Node.js, Deno or the Browser.

Get Last Array Item

const abc = ["a", "b", "c"];

lastItem(abc); //=> "c"

abc.at(-1); //=> "c"

Get N Last Array Items

const animals = ["Tiger", "Horse", "Lion"];

lastItem(animals, 2); //=> ["Horse", "Lion"]

animals.splice(-2); //=> ["Horse", "Lion"]

Similar Modules

array-last

This module is also quite fast, so I am including it as an alternative, I must mention that it has some bugs and open pull requests for several years and there seems to be no activity.

The biggest drawback of this module in my opinion is the poor error handling and it's strange behavior, here are some things I noticed.

• If you send an empty array it will return null

This module would throw a RangeError

• If you send a parameter that is not a number as length it will be changed to 1

This module would throw a TypeError

• If you send a number larger than the length of the array, the array will be filled with undefined.

last(["a", "b", "c"], 4); //=> [ undefined, 'a', 'b', 'c' ]

This module would throw a RangeError

• Does not handle if you send a negative number as expected length.

This module would throw a RangeError

Benchmarks

Check the benchmark code on bench.ts ⚡

Using Deno's built-in benchmark runner

benchmark       time (avg)             (min … max)       p75       p99      p995
-------------------------------------------------- -----------------------------
Slice        44.75 ns/iter  (39.73 ns … 801.56 ns)  42.69 ns  79.87 ns  80.45 ns
At           81.23 ns/iter  (79.83 ns … 104.44 ns)  81.35 ns  94.27 ns  94.68 ns
Array Last   13.93 ns/iter   (13.65 ns … 29.26 ns)   13.7 ns  15.01 ns  15.38 ns
Last Item    14.21 ns/iter    (12.7 ns … 19.77 ns)  14.87 ns  15.37 ns  15.51 ns

Version 0.1.2

Benchmarks are run on GitHub Actions on each commit, you can see the latest runs here.

Documentation

Is hosted on Deno Doc 📄

Support

Open an Issue, I will check it a soon as possible 👀

If you want to hurry me up a bit send me a tweet 😆

Consider supporting me on Patreon if you like my work 🙏

Don't forget to start the repo ⭐

Authors

Eliaz Bobadilla - Creator and Maintainer 💪

See also the full list of contributors who participated in this project ✨

Versioning

We use Semantic Versioning. For the versions available, see the tags 🏷️

Licence

Licensed under the MIT License 📄