stores_represent_ui_state.jsx

class SearchStore {
  @observable searchText;
  
  @action
  setSearchText = (searchText) => {
    this.searchText = searchText
  }
}

@observer
class SearchInput extends React.Component {
  
  handleInputChanged = (event) => {
    const { searchStore } = this.props;
    searchStore.setSearchText(event.target.value);
  }
  
  render() {
    const { searchStore } = this.props;
    return (
      <input
        value={searchStore.searchText}
        onChange={this.handleInputChanged}
      />
    );
  }
}