Transition + TransitionGroup does not animate on appear / enter (but does on exit) [codesandbox included]

[tianhuil]

What is the current behavior?

Transition + TransitionGroup does not animate on appear / enter (but does on exit). See https://codesandbox.io/s/adoring-villani-crjbs7?form-embed

This is in contrast to CSSTransition + TransitionGroup which works on appear, enter, and exit. See https://codesandbox.io/s/00rqyo26kn?from-embed

What is the expected behavior?

Should work with both Transition and CSSTransition

Could you provide a CodeSandbox demo reproducing the bug?

See above

[vidmantasa]

Hi! I see that no one answered you for several months so if you still haven't figured it out this is what you should do:

1. Set entering: { opacity: 0 },
2. Set timeout={{ enter: 0, exit: 500 }}

Here's working example

[wendyzhaogogo]

Will the bug be fixed?