stack-versus-heap.js

function aFunction() {
  // primitives are stored directly on the stack
  const foo = 1;
  
  // obects which do not escape the scope of a function will
  // be allocated on the stack and will be freed automatically
  // on return
  const bar = {
    stack: 123 
  };
  
  // object which escape the scope of the function will be allocated
  // on the heap and garbage collected once there are no more references
  // pointing to them
  const baz = {
    heap: 123
  }
  
  return baz;
}

// since the return is assigned to a value it will remain on the heap
let val = aFunction(); 

// now that we have set val to null the gc will have an opportunity to
// free the object
val = null;