I am trying to understand more about React, so I did some very simple test.
I know my test is NOT react way of doing things, but since it is still Javascript, I am just testing how everything is working for curiosity.
I declare a variable outside of react component, and every time the function component renders it will add 1 to the variable.
I activate the re-render by using a button, the button will activate an increase function then use a setState thus cause the component to re-render.
What I notice is the a variable is adding 1 twice, I put 2 console.log before and after it to monitor it. I can see there is one execution of adding, but where it the other adding coming from? The afteradding after rendering should be the same of next round's value before adding.
See the code, thanks in advance for any deeper understanding.
