storybook/addons/knobs/src/components/PropField.js

import PropTypes from 'prop-types';
import React from 'react';
import styled from 'react-emotion';

import TypeMap from './types';

const InvalidType = () => <span>Invalid Type</span>;

const Field = styled('div')({
  display: 'table-row',
  padding: '5px',
});
const Label = styled('label')({
  display: 'table-cell',
  boxSizing: 'border-box',
  verticalAlign: 'top',
  paddingRight: 5,
  paddingTop: 5,
  textAlign: 'right',
  width: 80,
  fontSize: 12,
  color: 'rgb(68, 68, 68)',
  fontWeight: 600,
});

export default class PropField extends React.Component {
  onChange = e => {
    this.props.onChange(e.target.value);
  };

  render() {
    const { onChange, onClick, knob } = this.props;

    const InputType = TypeMap[knob.type] || InvalidType;

    return (
      <Field>
        <Label htmlFor={knob.name}>{!knob.hideLabel && `${knob.name}`}</Label>
        <InputType knob={knob} onChange={onChange} onClick={onClick} />
      </Field>
    );
  }
}

PropField.propTypes = {
  knob: PropTypes.shape({
    name: PropTypes.string,
    value: PropTypes.any,
  }).isRequired,
  onChange: PropTypes.func.isRequired,
  onClick: PropTypes.func.isRequired,
};