Exposing onHeightReady hook

[nutgaard]

For when you need to animate scroll or elements outside of the collapse-component.

Don't know if this is the best solution, or even if it should be part of this library. But it did allow me to add scroll-animation alongside the expanding-component.

[nkbt]

I think doing "side-effect" (notifying parent) in componentWillReceiveProps is dangerous. It also would potentially end up in recursion.

Potentially this could be added to some other lifecycle method.

[nutgaard]

I'll look into using componentDidUpdate instead. Shouldn't really be a problem

[nkbt]

Thanks a lot for your PR. I guess it might be helpful to notify about current height, though I need to do some more testing with it.

Can you please, add an example of how you use it? That would help a lot to understand reasoning better for everyone (me included 😄)

[codecov-io]

Current coverage is 52.20%

Merging #43 into master will decrease coverage by -1.13% as of c885f2b

@@            master    #43   diff @@
=====================================
  Files           10     11     +1
  Stmts          135    159    +24
  Branches         0      0       
  Methods          0      0       
=====================================
+ Hit             72     83    +11
  Partial          0      0       
- Missed          63     76    +13

Review entire Coverage Diff as of c885f2b

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[nutgaard]

Fixed the issues highlighted in the initial review, and added an example of a potential usecase, autoscrolling, see example 7 and Hooks.js.

For simplicity I've included a devDependency for the scrolling.

[nkbt]

Sorry for the delay, was not able to check it properly

[nutgaard]

No problem. Just happy that it got merged. :)

Let me know if there is anything else you need me to do.