Reviving a 12K+ Star Abandoned Library: toastr-next v3 🍞

This is a submission for the GitHub Finish-Up-A-Thon Challenge

What I Built

toastr-next v3 a complete revival of CodeSeven/toastr, one of the most-starred abandoned JavaScript libraries on GitHub with 12,000+ stars and no meaningful commits since 2016.

toastr was the go-to notification library for millions of developers. But time wasn't kind to it. it required jQuery, had no TypeScript, no dark mode, no accessibility, and its Gulp + LESS build chain was completely dead. It was a library everyone knew but nobody could use in a modern project without guilt.

I picked it up, stripped it to the bones, and rebuilt it from scratch for 2026.

From this 👇🏻:

// 2015 — drag in jQuery just to show a toast
<script src="jquery.min.js"></script>  // 30 KB
<script src="toastr.min.js"></script>  // 5 KB
// Total: ~87 KB of dead weight

toastr.success('Hello!');

To this 👇🏻:

// 2026 — zero dependencies, full TypeScript, ~4 KB gzipped
import { toastr } from 'toastr-next';

const toast = toastr.success('Hello!');
await toast.dismissed; // Promise API!

~4 KB gzipped. No jQuery. No bloat. Just toasts. 🍞

Demo

Dark mode — toasts firing with progress bar

Light mode — same demo, toggled with the ☀️ button

🌐 Live Demo: toastr-next.vercel.app/

📦 npm: npmjs.com/package/toastr-next

🐙 GitHub: github.com/Divyesh-5981/toastr

The Comeback Story

Where it was

The original repo — abandoned since 2016, 12k stars, zero recent activity

What I built

🏗 TypeScript Rewrite (Zero Dependencies)

• No jQuery: 100% strict TypeScript with full JSDoc.
• Universal Formats: Ships in ESM, CJS, UMD, and IIFE (works from Vite to raw <script> tags).

🎨 CSS-First Theming

• Modern CSS: Uses CSS variables instead of inline JS styles.
• Themes & Motion: Auto dark mode (prefers-color-scheme), manual toggle (localStorage), and prefers-reduced-motion support.
• Layouts: 4 pure CSS animation presets (Fade, Slide, Bounce, Flip) and native RTL support.

♿ Full Accessibility (WCAG 2.1 AA)

• Screen Readers: Dynamic ARIA live regions (alert/status) and atomic labels.
• Keyboard Navigation: Escape key to close, Tab focus management, and pause-on-focus protection.

🔌 Modern API

• Async & Events: Promises (await toast.dismissed) and lifecycle event subscriptions (toastr.subscribe).
• DX & Security: Automatic CSS injection (no separate stylesheet import), native React wrapper (useToastr), and built-in XSS protection.

📦 Production Ready

• Lightweight: ~4 KB gzipped (~2 KB JS + ~2 KB CSS) vs the original ~87 KB jQuery version.
• Live: Available on npm as toastr-next with a live Vercel demo.

Size comparison

My Experience with GitHub Copilot

I used GitHub Copilot as a pair programmer throughout the entire revival not for autocomplete, but as a genuine collaborator at every architectural decision.

Here's exactly how it helped, step by step.

1. Deciding what to keep

Before writing a single line, I needed to know what was worth saving from 14 years of jQuery-tangled code.

Prompt:

"Here is the original toastr v2 source. What's worth keeping
for backward compatibility and what should be completely rewritten?"

Copilot identified the API surface success, error, info, warning — as the only thing worth preserving. Everything underneath needed to go. This became the guiding rule for the entire rewrite.

2. TypeScript interfaces

With the API surface locked, I needed a clean type system built around it.

Prompt:

"Design TypeScript interfaces for ToastrOptions, ToastResponse,
and ToastEvent. I want every toast call to return a Promise
that resolves when the toast is dismissed."

Copilot designed all three interfaces. The standout was the dismissed: Promise<void> pattern on ToastResponse making every toast awaitable:

const { dismissed } = toastr.success('Changes saved');
await dismissed;
// runs after the toast closes

I didn't ask for this pattern specifically. Copilot suggested it unprompted, and it became the most-loved feature of the rewrite.

3. Theming system

I wanted dark mode to work automatically and be manually overridable without JavaScript touching the CSS side.

Prompt:

"I need a CSS theming system that supports auto dark mode via
prefers-color-scheme AND manual override via a data-theme attribute
on the html element. No JavaScript should be needed for the CSS side."

Copilot proposed the [data-theme] + @media (prefers-color-scheme) layering pattern. The media query handles auto mode; a single attribute flip handles manual override. No JS. No flicker. Just CSS doing its job.

4. Accessibility

I had applied role="alert" to all four toast types, assuming it was correct. I asked Copilot to review before shipping.

Prompt:

"What ARIA roles and aria-live values should toast notifications use
to be WCAG 2.1 AA compliant? Should all toasts use the same role?"

Copilot flagged that role="alert" is assertive it interrupts a screen reader mid-sentence. That's right for errors and warnings, but jarring for a success message. The fix:

A subtle WCAG 2.1 distinction I would have shipped wrong without this review.

5. CSS auto-injection

Early users kept asking why they had to import the CSS separately. That broke the drop-in promise. I needed the stylesheet bundled inside the JS, self-injecting on import.

Prompt:

"Write a Vite generateBundle plugin that reads the extracted CSS asset
and injects it into every JS chunk as a self-executing style injector.
Add a guard so it only injects once even if the module is imported multiple times."

Copilot drafted the complete Rollup plugin in one shot the generateBundle hook, CSS-to-string conversion, and a data-toastr-styles sentinel attribute as the double-injection guard. I reviewed it, made minor tweaks, and it worked first try.

This was the most technically complex Copilot collaboration in the project and the one that impressed me most.

6. Demo page

The final piece was a demo site that actually showed off everything that changed.

Prompt:

"Build a demo page for toastr-next with a quick fire section,
a live playground with dropdowns for type/animation/position,
an animation showcase, a before/after comparison, and a light/dark
theme toggle that persists to localStorage."

Copilot built the full index.html iteratively playground, comparison table, custom ARIA dropdown, and the light/dark toggle with localStorage persistence. I directed; it executed. The entire demo came together in an afternoon.

What I took away

Copilot wasn't writing boilerplate it was catching real bugs, proposing patterns I hadn't considered, and solving problems I didn't know how to start. The dismissed: Promise<void> feature, the WCAG role distinction, and the Rollup plugin were all things I got from Copilot that I would not have shipped on my own.

That's the kind of collaboration this challenge is designed to reward.

After the main rewrite, I ran the entire codebase through GitHub Copilot to audit for hidden anti-patterns and code smells. It helped me spot subtle optimizations and edge cases, allowing me to refine the code into a truly polished, production-grade architecture.

The audit - for hidden anti-patterns and code smells.

Improvements - for hidden anti-patterns and code smells.

Working with Copilot felt less like using a tool and more like having a senior developer who knew every API, caught every edge case, and never got tired. The revival that would have taken weeks took days.

Acknowledgements

Huge respect to the original authors — John Papa, Tim Ferrell, and
Hans Fjällemark - who built something so good that developers were still reaching for it a decade later.

This revival exists because their original work was worth finishing ❤️