[FormControl] Convert to function component

[joshwooding]

• I have followed (at least) the PR section of the contributing guide.

[mui-pr-bot]

@material-ui/core: parsed: -0.14% 😍, gzip: -0.10% 😍

Details of bundle changes.

Comparing: 496b0ff...148ea35

bundle	parsed diff	gzip diff	prev parsed	current parsed	prev gzip	current gzip
@material-ui/core	-0.14%	-0.10%	349,674	349,168	90,015	89,925
@material-ui/core/Paper	0.00%	-0.03%	68,366	68,366	20,042	20,035
@material-ui/core/Paper.esm	0.00%	+0.01% 🔺	60,732	60,732	18,787	18,788
@material-ui/core/Popper	0.00%	-0.01%	34,825	34,825	11,883	11,882
@material-ui/core/styles/createMuiTheme	0.00%	0.00%	17,877	17,877	5,961	5,961
@material-ui/core/useMediaQuery	0.00%	-0.19%	2,469	2,469	1,042	1,040
@material-ui/lab	0.00%	0.00%	147,879	147,879	43,786	43,786
@material-ui/styles	0.00%	+0.01% 🔺	53,105	53,105	15,424	15,425
@material-ui/system	0.00%	+0.02% 🔺	17,136	17,136	4,525	4,526
Button	0.00%	-0.00%	88,467	88,467	26,284	26,283
Modal	0.00%	-0.00%	82,583	82,583	24,780	24,779
colorManipulator	0.00%	0.00%	3,745	3,745	1,538	1,538
docs.landing	0.00%	0.00%	49,914	49,914	10,815	10,815
docs.main	0.00%	0.00%	645,771	645,771	200,653	200,653
packages/material-ui/build/umd/material-ui.production.min.js	-0.15%	-0.07%	298,116	297,681	82,865	82,806

Generated by 🚫 dangerJS against 148ea35

[oliviertassinari]

Wow, at first I was like: wtf is this. But then, looking twice at the logic, it looks valid 👌.

[eps1lon]

This is the function component version of

static getDerivedStateFromProps(props, state) {
  if (props.disabled && state.focused) {
    return { focused: false };
  }
  return null;
}

Hooks FAQ: How do I implement getDerivedStateFromProps?

[oliviertassinari]

Thanks for the link.