Using a for loop for dynamic objects

[Colin]

In future please post code using the method in this link. How to share code or flow json

You are overwriting msg.call the first time round the loop, which destroys what was there before, so the next time you execute that line there is no data there.
Also you should not use for in for an array you should use forEach() or a simple for loop. JavaScript Array Iteration

Do you not want to use the map method? It is much simpler.