hyper/lib/store/write-middleware.js

import terms from '../terms';

// the only side effect we perform from middleware
// is to write to the react term instance directly
// to avoid a performance hit
export default () => next => action => {
  if (action.type === 'SESSION_PTY_DATA') {
    const term = terms[action.uid];
    if (term) {
      term.write(action.data);
    }
  }
  next(action);
};