Everyone figured you’d shell out for LeetCode Premium if you wanted to debug your JavaScript solutions mid-practice.
That’s the deal — fork over cash for breakpoints, step-throughs, the works.
But this tiny open-source repo just shattered that assumption. It packs LeetCode test cases into a local playground, runnable straight from VS Code. No subscriptions. No browser lag. Just you, your code, and a debugger that actually listens.
Look, I’ve grilled dozens of devs on interview prep rituals. LeetCode dominates. But that paywall for debugging? It’s the silent killer — folks hack around it with notebooks or half-baked scripts. This changes the game: full fidelity practice, free, on your machine.
Why LeetCode’s Paywall Feels Like a Cash Grab
The original creator nails it right out of the gate:
Leetcode debugging feature sits behind paywall. Stop paying for that!
Spot on. LeetCode’s free tier teases problems, sure. But debugging? That’s premium territory — $35/month or whatever they’re charging now. (And don’t get me started on the corporate plans.)
It’s not just annoying; it’s architecturally shortsighted. Browser-based debuggers choke on complex state. You can’t rewind easily, inspect deeply, or tweak on the fly. Meanwhile, VS Code — with its zero-config Jest/Vitest extensions — turns your laptop into a LeetCode-killer.
This repo sidesteps all that. Clone, npm install, done. Problems live in leetcode-playground/[problemname].js. Tests? Grouped neatly under /tests. Fire up Vitest, hit debug, and boom — breakpoints wherever you want.
How to Run LeetCode Locally (Step-by-Step Reality Check)
Here’s the thing: setup’s dead simple, but don’t expect miracles on day one.
Clone the repo. npm install. Crack open a file like two-sum.js or whatever Blind 75 classic you’re tackling. The Jest/Vitest runner extension (grab “Vitest runner by firsttris” — it’s gold) spots your tests automatically. Click ‘debug’ on a specific case or describe block. Debugger attaches. Step through your mistaken array splice or whatever.
I tested it myself last night — nailed a medium problem I’d bombed online. Why? Local speed. No network blips. And those test cases? They’re battle-tested mirrors of LeetCode’s, with room for you to contribute more. Covers Blind 75 now; top 150 incoming, aiming for all 3K eventually.
But — and this is my unique angle — it’s echoing the early days of HackerRank clones. Remember when devs built custom runners for TopCoder because the platform sucked? This feels like that pivot: user-built tools outpacing the mothership. LeetCode’s probably sweating; their PR spin about ‘premium value’ rings hollow when free alternatives debug better.
Is Local Debugging Really Better Than LeetCode Premium?
Damn right it is, for JS folks. Premium’s slick in-browser, yeah. But VS Code? Infinite extensibility.
Pair it with GitHub Copilot for hints (without spoiling), or wallaby.js for instant test feedback. LeetCode can’t touch that ecosystem. And architecturally? Local means your data stays yours — no telemetry feeding their algo farms.
The ‘how’ here is Vitest’s magic: it runs tests in Node, attaches Chrome debugger smoothly. Why does it matter? Practice loops tighten. You spot edge cases faster — null inputs, massive arrays — without Premium’s throttles. One dev I pinged said it halved his solve time on hards.
Drawbacks? Coverage ain’t total yet. Blind 75’s solid, but if you’re grinding company-tagged lists, you might supplement. Still, for JS grinders prepping FAANG? This repo’s your new baseline.
Why Does This Matter for JavaScript Interview Prep?
Interviews haven’t changed: crush LeetCode, or bust. But tools have.
This repo forces a shift — from passive browser consumer to active local tinkerer. It’s not hype; it’s empowerment. Predict this: within a year, forks will explode, covering every language. Python next? Rust? The open-source hive mind will deliver.
LeetCode’s response? Crickets so far. Their playground’s getting long in the tooth — clunky UI, no real extensions. This? Pure dev joy.
Tips from the frontlines: Use VS Code’s outline view for test groups. Set conditional breakpoints on failures. Contribute tests — it’s git-push easy.
And yeah, debug mode’s the killer app. As the creator says: “I find debug mode is the most useful feature to figure out where i did mistake during practice.”
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Frequently Asked Questions
How do I run LeetCode problems locally in VS Code?
Clone the repo, npm install, install Vitest runner extension. Open a problem .js file, click debug on tests.
What’s the best VS Code extension for LeetCode debugging?
“Jest/Vitest runner by firsttris” — attaches debugger to specific cases instantly.
Does this repo cover all LeetCode problems?
Blind 75 now, top 150 soon, expanding to 3K. Contribute your own tests!
