What should I study first?

Short explanation:

Preparation works best when later topics build on earlier ones. JavaScript scope and async behavior support Node and React; database rules support backend correctness and system design. Follow the sequence, but spend extra time where you cannot yet explain a concept without reading the answer.

Key points:

• Start with JavaScript, async code, Node.js and HTTP.

• Then study NestJS, databases, React and system design.

• Use the numbered files in order; revise weak topics again.

• For each topic, read the definition, run or trace an example and explain one failure case aloud.

Interview point:

• Use revision notes to recall an already understood concept, not as a substitute for learning why it works.