IconAlerts.tsx

import React from 'react';
import { makeStyles, Theme, createStyles } from '@material-ui/core/styles';
import Alert from '@material-ui/lab/Alert';
import CheckIcon from '@material-ui/icons/Check';
import CheckCircleOutlineIcon from '@material-ui/icons/CheckCircleOutline';

const useStyles = makeStyles((theme: Theme) =>
  createStyles({
    root: {
      width: '100%',
      '& > * + *': {
        marginTop: theme.spacing(2),
      },
    },
  }),
);

export default function IconAlerts() {
  const classes = useStyles();

  return (
    <div className={classes.root}>
      <Alert icon={<CheckIcon fontSize="inherit" />} severity="success">
        This is a success alert—check it out!
      </Alert>
      <Alert iconMapping={{ success: <CheckCircleOutlineIcon fontSize="inherit" /> }}>
        This is a success alert—check it out!
      </Alert>
      <Alert icon={false} severity="success">
        This is a success alert—check it out!
      </Alert>
    </div>
  );
}