foundation

JavaScript Core

Types, scope, functions, prototypes, async execution, modules, memory, and runtime differences.

Strong JavaScript interview answers connect language semantics with runtime behavior. Closures explain module state, hooks, event handlers, and memory retention — not just syntax. Equality questions test whether you avoid implicit coercion on critical paths.

Focus areas: types and coercion, lexical scope, functions, objects and prototypes, async scheduling, module systems, memory, and browser versus Node APIs.

Checklist:

Tie each concept to expected behavior in code.
Name production trade-offs, not only definitions.
Use child topics for depth on each focus area.