how get get file name in file chooser in react?

You can get selected file name without using ref

  function handleChange(event) {
    console.log(`Selected file - ${event.target.files[0].name}`);
  }

  <input type="file" onChange={handleChange} />

Good documentation and example taken from here, explaining what you are trying to do. https://reactjs.org/docs/uncontrolled-components.html#the-file-input-tag

Codepen: https://codepen.io/anon/pen/LaXXJj

React.JS contains a specific File API to use.

The following example shows how to create a ref to the DOM node to access file(s) in a submit handler:

HTML

<input type="file" />

React.JS

class FileInput extends React.Component {
  constructor(props) {
    super(props);
    this.handleSubmit = this.handleSubmit.bind(this);
    this.fileInput = React.createRef();
  }
  handleSubmit(event) {
    event.preventDefault();
    alert(
      `Selected file - ${
        this.fileInput.current.files[0].name
      }`
    );
  }

  render() {
    return (
      <form onSubmit={this.handleSubmit}>
        <label>
          Upload file:
          <input type="file" ref={this.fileInput} />
        </label>
        <br />
        <button type="submit">Submit</button>
      </form>
    );
  }
}

ReactDOM.render(
  <FileInput />,
  document.getElementById('root')
);

Alert Filename

alert(`Selected file - ${this.fileInput.current.files[0].name}`);

Cited: React.JS Documentation | Examples