Check your understanding

A timer is a host API. V8 executes the JavaScript callback; the browser arranges its later invocation.

AST nodes describe program constructs; their connections show how those constructs are nested. In V8, the bytecode generator uses this tree to create instructions.

Optimized code can rely on particular value types. When that assumption no longer holds, deoptimization restores the function's state so execution can continue through the interpreter.

Each function call has its own data. A stack frame stores the call's state and the information needed to resume execution after return.

Assigning null changes only the value of b. The value of a stays the same, so the object remains accessible through a.

GC retains the scene while references still lead to it. The code responsible for closing the scene must remove connections that are no longer needed.