react reset file input

1e.target.value = null;

1functionThatResetsTheFileInput() {
2  let randomString = Math.random().toString(36);
3
4  this.setState({
5    theInputKey: randomString
6  });
7}
8
9render() {
10  return(
11    <div>
12      <input type="file"
13             key={this.state.theInputKey || '' } />
14      <button onClick={this.functionThatResetsTheFileInput()} />
15    </div>
16  )
17}
18