FrontendHaltJavaScript·Intermediate·Conceptual·1 min read
What is a lexical environment record?
Short interview answer
It is a specification-level structure mapping identifiers to bindings, optionally linked to an outer environment. Identifier resolution walks that chain. It is a better model than imagining variables as properties of the call stack.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.