What Javascript Syntax is This format function()()?

Question

In material UI doc, there's this:

styled(Button)({
boxShadow: 'none',
  textTransform: 'none',
  fontSize: 16,
  padding: '6px 12px',
  border: '1px solid',
  lineHeight: 1.5,
  backgroundColor: '#0063cc',
  borderColor: '#0063cc',
  fontFamily: [
    '-apple-system',
    'BlinkMacSystemFont',
    '"Segoe UI"',
    'Roboto',
    '"Helvetica Neue"',
    'Arial',
    'sans-serif',
    '"Apple Color Emoji"',
    '"Segoe UI Emoji"',
    '"Segoe UI Symbol"',
  ].join(','),
  '&:hover': {
    backgroundColor: '#0069d9',
    borderColor: '#0062cc',
    boxShadow: 'none',
  },
  '&:active': {
    boxShadow: 'none',
    backgroundColor: '#0062cc',
    borderColor: '#005cbf',
  },
  '&:focus': {
    boxShadow: '0 0 0 0.2rem rgba(0,123,255,.5)',
  },
});

But what is this syntax? styled()() ? Is this Javascript? There's a toggle to switch between Javascript and Typescript, but I already set it to Javascript and the syntax is still styled()(), what does it means? Is this some kind of ES6 syntax?

EDIT: Apparently this is higher order function. Never knew before that it can be written like this: blablabla()();