add React.memo to avoid unnecessary re-render

[chentsulin]

97

After these changes, we can wrap functions with useCallback to avoid unnecessary re-render

import React, { useCallback } from 'react';
import { render } from 'react-dom';
import WordCloud from 'react-d3-cloud';
import { scaleOrdinal } from 'd3-scale';
import { schemeCategory10 } from 'd3-scale-chromatic';

function App() {
  const data = [
    { text: 'Hey', value: 1000 },
    { text: 'lol', value: 200 },
    { text: 'first impression', value: 800 },
    { text: 'very cool', value: 1000000 },
    { text: 'duck', value: 10 },
  ];

  const fontSize = useCallback((word) => Math.log2(word.value) * 5, []);
  const rotate = useCallback((word) => word.value % 360, []);
  const fill = useCallback((d, i) => scaleOrdinal(schemeCategory10)(i), []);
  const onWordClick = useCallback((word) => {
    console.log(`onWordClick: ${word}`);
  }, []);
  const onWordMouseOver = useCallback((word) => {
    console.log(`onWordMouseOver: ${word}`);
  }, []);
  const onWordMouseOut = useCallback((word) => {
    console.log(`onWordMouseOut: ${word}`);
  }, []);

  return (
    <WordCloud
      data={data}
      width={500}
      height={500}
      font="Times"
      fontStyle="italic"
      fontWeight="bold"
      fontSize={fontSize}
      spiral="rectangular"
      rotate={rotate}
      padding={5}
      random={Math.random}
      fill={fill}
      onWordClick={onWordClick}
      onWordMouseOver={onWordMouseOver}
      onWordMouseOut={onWordMouseOut}
    />
  );
);