Tried using react hooks

[benishouga]

What I did

• Use react@next and react-dom@next 3285db5 (The latest d.ts corresponds to hooks.)
• Just replace it, replace it, replace it.
• Sometimes, commonized API access.

Impressions

pros

• Simple components have a very good outlook. 9d46d3c
• It is easier to make common processing depending on the life cycle. 29e9cc0

cons

• There are cases in which it becomes complicated. 514ce4d
• The instance variable State was easy to use. When this became a local variable, things to consider increased.

code

before

src/main/client$ sloc .
---------- Result ------------
            Physical :  3685
              Source :  3310
             Comment :  11
 Single-line comment :  10
       Block comment :  1
               Mixed :  10
               Empty :  374
               To Do :  0
Number of files read :  50
------------------------------

after

src/main/client$ sloc .
---------- Result ------------
            Physical :  3294
              Source :  2967
             Comment :  11
 Single-line comment :  10
       Block comment :  1
               Mixed :  11
               Empty :  327
               To Do :  0
Number of files read :  55
------------------------------