JavaScript LHS and RHS Lookup

Question

I was reading the Scopes and Closure of You don't know JS book by Kyle Simpson, specifically this topic Compiler Speak.

There they mention the LHS and RHS lookup. I am failed to understand these two terms, can anyone help me to realize them?

Answer 1

LHS look-up is done when a variable appears on the left-hand side of an assignment operation, and an RHS look-up is done when a variable appears on the right-hand side of an assignment operation.

I think of it as follows :
lhs lookup is a container lookup
rhs lookup is a value lookup