Change form values based on other form siblings. about formik HOT 2 CLOSED

Just write your own change handler. You can call setValues directly to set the value of the field you're updating and its sibling's values. The set of available options for the sibling select can be kept in your component state, so just update that with setState.

Something like:

handleDropdownChange = (e: React.ChangeEvent<HTMLSelectElement>) => {
  const siblingOptions = e.target.value == 'foo' ? ['bar', 'baz'] : ['bap'];
  this.props.setValues( { ...this.props.values,
                          myDropdown: e.target.value,
                          mySibling: siblingOptions[0] });
  this.setState( { siblingOptions: siblingOptions });
}

from formik.

haven't pushed 0.8 so setValues above will be handleChangeValue fyi.

from formik.