Change to use react-intersection-observer

[aricallen]

Hi, I started using your package. Its really awesome! While integrating with my app I noticed a few eslint issues and also saw that you could benefit from moving to react-intersection-observer. (https://github.com/stephane-monnot/react-vertical-timeline/issues/63)

Since you have saved me a bunch of time by providing this lovely package, I felt inspired to at least contribute back with some updates. Hope you find it helpful.

Fixes

• dateClassName was missing from propTypes.
• updates to use useInView hook for leveraging intersection observer
• updates jest tests to include mockAllIsIntersecting

One thing to note is that depending on your comfort level with browser support, window.IntersectionObserver is still relatively new, so you may want to include a polyfill. Browser support is pretty solid at this point, but up to you. Let me know if you want me to include that in this PR or not.

Reference: https://github.com/thebuilder/react-intersection-observer#polyfill Browser support: https://caniuse.com/#feat=intersectionobserver

[codecov-commenter]

Codecov Report

Merging #67 into master will increase coverage by 12.50%. The diff coverage is 100.00%.

@@             Coverage Diff              @@
##           master       #67       +/-   ##
============================================
+ Coverage   87.50%   100.00%   +12.50%     
============================================
  Files           2         2               
  Lines          16        10        -6     
  Branches        2         0        -2     
============================================
- Hits           14        10        -4     
+ Misses          2         0        -2     

Impacted Files	Coverage Δ
src/VerticalTimelineElement.js	100.00% <100.00%> (+16.66%)	:arrow_up:

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[stephane-monnot]

Great !! I will check it soon and merge asap.