react proptypes reuse shape

// File lib/PropTypeValues.js
import { PropTypes } from 'react';

export let MemoryPropTypes = PropTypes.shape({
  memoryID: PropTypes.number,
  content: PropTypes.string,
  date: PropTypes.object,
  dateStr: PropTypes.string,
  note: PropTypes.string
}).isRequired

// MemoryForm.jsx
import { MemoryPropTypes } from './lib/PropTypeValues'
import React from 'react';

class MemoryForm extends React.Component {
  static propTypes: {
    memory: MemoryPropTypes,
    // ...
  };
}