...

class App extends Component {
  constructor() {
    this.state = {
      ...
      text: null,
    }

    ...
    this.handleInput = this.handleInput.bind(this);
  }

  ...

  handleInput(metaInformation) {
    this.setState({
      text: metaInformation.text,
    });
  }

  render() {
    return (
      <div
        style={{
          position: 'relative'
        }}
      >
        <InputTrigger
          trigger={{
            keyCode: 50,
            shiftKey: true,
          }}
          onStart={(metaData) => { this.toggleSuggestor(metaData); }}
          onCancel={(metaData) => { this.toggleSuggestor(metaData); }}
          onType={(metaData) => { this.handleInput(metaData); }}
        >
          ...
        </InputTrigger>

        <div
          id="dropdown"
          style={{
            ...
          }}
        >
          {
            this.state.users
              .filter(user => user.indexOf(this.state.text) !== -1)
              .map(user => (
                <div
                  style={{
                    padding: '10px 20px'
                  }}
                >
                  { user }
                </div>
              ))
          }
        </div>
      </div>
    );
  }
}

...