Others — JavaScript, Angular & React

How these tracks are organised

Each of the three tracks follows the same shape, so you can move between them without relearning how to study. Fundamentals come first — the language or framework's execution model, the mental model you need before anything else makes sense. Core APIs follow, then the patterns practitioners reach for daily, then performance and testing, and finally the advanced material that separates a mid-level answer from a senior one. Every topic states the problem it solves before showing the solution, because interviewers almost always follow "what is it?" with "why would you use it?".

What each topic page contains

A topic page opens with intent — one sentence on what the concept is for. Then comes a full written explanation, the specific problem the concept solves, a walkthrough of how it works under the hood, and a plain-language analogy for when the mechanics have not clicked yet. After that you get an explicit "when to use" list, a "watch out for" list of the traps that cost candidates offers, and a runnable code example. Nothing is a one-line definition; the whole point is that you can answer the follow-up question, not just the first one.

Freshers versus experienced candidates

The same topic is asked very differently depending on your level. A fresher is usually asked to define a concept and give an example. An experienced candidate is asked about trade-offs, failure modes, and what they would do differently at scale. Topics are tagged by difficulty so you can prioritise: if you have three years of experience, the fundamentals are a quick refresher and the performance, testing and advanced clusters are where interviews are actually won or lost.

How to use these tracks

Read a cluster end to end rather than cherry-picking single topics — the questions build on each other, and interviewers probe the connections between them. Type the code examples out rather than reading them; the muscle memory matters when you are asked to write on a whiteboard or in a shared editor. Then close the page and try to explain the concept aloud in your own words. If you cannot get through the "watch out for" list from memory, that topic is not ready yet.