Possible problem with quiz question: changing state in render() method

Hi,

It seems to me the following question is graded incorrectly. I don't recall specific discussion in the training videos that addresses this precise situation, but it seems to go against the idea of render USING the state to decide how and what to render. If render CHANGES the state, then we might end up with a complex series of re-renders, with the risk that these state-changing render calls may never terminate if our logic is faulty or badly designed.

Let me know if I'm missing something or wrong.

Thanks,

Jere

Quiz Question 1 of 5

It is acceptable to modify your state information in the render() method to make it acceptable for display.

My chosen answer: False

Response: Bummer! Unfortunately, that answer is incorrect.

SOURCES SUGGESTING THE ANSWER IS INCORRECT:

URL: https://facebook.github.io/react/docs/react-component.html#render

The render() function should be pure, meaning that it does not modify component state, it returns the same result each time it's invoked, and it does not directly interact with the browser.

URL: https://github.com/facebook/react/issues/5591 title: Calling setState in render causes infinite loop #5591

- includes comments like:

jimfb commented on Dec 3, 2015

In general, this should never happen; you should not be doing anything remotely related to modifying any component's state within a render function.

I'm curious what your use case is, for having a callback which does a setState; mind sharing?