function getRange(limit) {
  let range = [];

  for (let i = 0; i < limit; i++) {
    range.push(i);
  }

  return range;
}

class App extends React.Component {
  state = {
    numbers: [1, 2, 3, 4, 5, 6],
    limit: 7
  };

  handleLimitChange = e => {
    const limit = e.target.value;
    const limitChanged = limit !== this.state.limit;
    if (limitChanged) {
      this.setState({ limit, numbers: getRange(limit) });
    }
  };

  render() {
    return (
      <div>
        <input
          onChange={this.handleLimitChange}
          placeholder="limit"
          value={this.state.limit}
        />
        {this.state.numbers.map((number, idx) => (
          <p key={idx}>{number} </p>
        ))}
      </div>
    );
  }
}

const rootElement = document.getElementById("root");
ReactDOM.render(<App />, rootElement);