fix: use mounted property, replace mounted state, resolves #16290

[rinick]

🤔 This is a ...

• Bug fix

👻 What's the background?

resolves issue : destroyed Menu right after it's created will cause React warning #16290

💡 Solution

use mounted property instead of mounted state

☑️ Self Check before Merge

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

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[codecov]

Codecov Report

Merging #16322 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #16322      +/-   ##
==========================================
+ Coverage   95.28%   95.35%   +0.07%     
==========================================
  Files         253      253              
  Lines        6780     6776       -4     
  Branches     1956     1968      +12     
==========================================
+ Hits         6460     6461       +1     
+ Misses        319      314       -5     
  Partials        1        1

Impacted Files	Coverage Δ
components/menu/index.tsx	97.34% <100%> (-0.1%)	⬇️
components/_util/wave.tsx	88.46% <0%> (+2.88%)	⬆️
components/_util/openAnimation.tsx	75% <0%> (+7.14%)	⬆️

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[codecov]

Codecov Report

Merging #16322 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #16322      +/-   ##
==========================================
+ Coverage   95.28%   95.35%   +0.07%     
==========================================
  Files         253      253              
  Lines        6780     6776       -4     
  Branches     1956     1968      +12     
==========================================
+ Hits         6460     6461       +1     
+ Misses        319      314       -5     
  Partials        1        1

Impacted Files	Coverage Δ
components/menu/index.tsx	97.34% <100%> (-0.1%)	⬇️
components/_util/wave.tsx	88.46% <0%> (+2.88%)	⬆️
components/_util/openAnimation.tsx	75% <0%> (+7.14%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 685f433...e1f62ac. Read the comment docs.

[zombieJ]

This should fix in raf instead of change to this.mounted = xxx.

[zombieJ]

close since #16370

[rinick]

This should fix in raf instead of change to this.mounted = xxx.

@zombieJ
would this still cause an unnecessary render() ?
I think the whole point of using state is because we want to let react framework decide when to render.
if set mounted=true doesn't require a re-render, then there is no reason to use state

[zombieJ]

Since React will release concurrent mode in ~Q2 2019, we use this.state instead of this.[variable] to ensure it not breaks in concurrent mode.
I know use this.[variable] is still safe in some condition, but use pure state is much easier.