JavaScript
Build instincts for runtime behavior, references, closures, promises, and async failures.
Solve real React, JavaScript, TypeScript, Node.js, and DSA challenges. Get hints, code feedback, and a clearer practice path as you build interview-ready habits.
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Challenge 03
Practice a focused algorithm problem, verify edge cases, and review the quality of your approach.
def sum_two_numbers(a, b):
return a + b
# Try a few inputs
result = sum_two_numbers(4, 7)
Run the visible examples to check your solution.
Your code quality review appears after the tests pass.
Choose a track and try a lightweight version of the Codstak workflow.
Interview practice tracks
Start with the track that matches your gap. When you need help, AI Coach can explain the problem, give a hint, or review what your solution demonstrates.
See the frontend interview prep pathBuild instincts for runtime behavior, references, closures, promises, and async failures.
Learn type annotations, objects, unions, and safe everyday patterns step by step.
Build interview-style interfaces with state, effects, forms, accessibility, and feedback.
Practice HTTP contracts, validation, authorization, webhooks, and resilient API behavior.
Strengthen your core data structures and algorithmic thinking through focused exercises.
How it works
Codstak is built around solving problems, not reading endless lists before you touch the code.
Work on practical interview tasks across React, JavaScript, TypeScript, Node.js, and DSA.
Use contextual hints and explanations when you are stuck without jumping straight to the final answer.
Run tests, inspect feedback, and use your attempt history to choose a better next practice step.
AI coach
Ask for a hint, understand an error, or get your solution reviewed. The coach helps you reason through the next step so you can keep practicing instead of immediately revealing the solution.
Codstak Coach
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Free
An open practice library for building fundamentals, trying interview-style problems, and working at your own pace.
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ProProgressive guidance while you practice, debug, and review your solutions.
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When I'm genuinely stuck
Hints over 3 months
144
AI Coach gives you plenty of room at this pace.
That's 144 hints — the 3-month AI Coach plan includes 1,200.
Codstak Pro is built around guided progression and skill feedback. It does not guarantee an interview outcome.
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