How to bind input values ​​in React?

Question

JavaScript

In the second step of the form validation, there are two inputs: Cities and Countries.
It is necessary that when one of the Countries is selected, the cities of the selected country are displayed
Link to the project
https://codesandbox.io/s/form-task-oryj0

Answer 1

getCitiesOptions = () => {
  const country = +this.state.country;

  return Object.entries(cities)
    .filter(n => n[1].country === country)
    .map(([ id, city ]) => (
      <option key={id} value={id}>
        {city.name}
      </option>
    ));
}