Copied from https://medium.com/@matuzo/getting-started-with-css-font-loading-e24e7ffaa791

css-font-loading-api.js

var notoSansRegular = new FontFace('Noto Sans Regular', 'url(/fonts/NotoSans-Regular.woff2)', {
    style: 'normal',
    weight: '400'
});
// add new font
document.fonts.add(notoSansRegular);
// load font
notoSansRegular.load();
//check status
notoSansRegular.loaded.then((fontFace) => {
  // This is where you can declare a new font-family, because the font is now loaded and ready.  
  console.info('Current status', fontFace.status);
  console.log(fontFace.family, 'loaded successfully.');
// Throw an error if loading wasn't successful
}, (fontFace) => {
  console.error('Current status', notoSansRegular.status);
});