Instruction: Describe the call stack mechanism and its role in function execution.
Context: This question evaluates the candidate's understanding of the JavaScript execution model and how function calls are managed.
Official answer available
Preview the opening of the answer, then unlock the full walkthrough.
The call stack, in JavaScript, is a data structure that records where in the program we are. If we step into a function, we push something onto the stack. If we return from a function, we pop off the top of the stack. This is how the JavaScript engine keeps track of function calls.
When a script calls a function, the interpreter adds it to the call stack and then starts carrying out the function. Any functions that are called by that function are added to the call stack further up, and run where their calls are reached. When the current function is finished, the interpreter takes it off the stack and resumes execution where it left...