A JavaScript engine generally consists of a baseline compiler that works on the compilation of the code in the form of intermediate representation (IR) /byte code and then passes the byte code to the interpreter. The JavaScript engine works on the JavaScript source code and puts it and then executes the compilation to binary instructions (machine code) that are easily understandable by the CPU. The call stack just has the reference or memory address of where these function definitions and objects are stored and would appear on the search engine. While function definitions and objects are not stored inside the call stack, they are stored inside the memory heap. Primitive values like int, bool, etc are stored inside the call stack. It is defined as an object which stores local variables, functions, and objects of the codes and how would they appear on the screen. The call stack stores the execution context or code for each function. The Call stack is a data structure that functions on the Last In First Out (LIFO) principle.

The memory occupied in the heap continues to exist even after JavaScript code execution has been completed and is later removed by the JavaScript Garbage Collector if needed. Individual data elements distributed on the heap are typically released in ways that are asynchronous from one another. The memory heap is where the memory allocation happens, it is a location in memory where memory may be allocated at random access. Heap is a large unstructured data structure that stores all the dynamic data like function definitions, objects, arrays, etc.

‍ The engine consists of two main elements: Memory Heap

Javascript source code